JP5352133B2 - Photoelectric conversion material, photoelectric conversion element, and solid-state imaging element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric converting material, a photoelectric converting element, and a solid-state image sensor that sufficiently absorb light in the infrared range, have high sensitivity, and reduce a dark current. <P>SOLUTION: The photoelectric converting material contained in a photoelectric converting film generating electric charges corresponding to incident light contains a squarylium compound expressed by the formula SQ-1 and a naphthalocyanine compound expressed by the formula NP-1. Here, A and B are each independently a substituent which is bonded at sp<SP>2</SP>carbon, M is a metal atom, and R<SB>4</SB>to R<SB>27</SB>are each independently a hydrogen atom or substituent. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an organic photoelectric conversion material, a photoelectric conversion element, and a solid-state imaging element, and in particular, a photoelectric conversion element including a pair of electrodes and a photoelectric conversion film provided between the pair of electrodes, and the photoelectric conversion film It is related with the photoelectric conversion material contained and a solid-state image sensor provided with this photoelectric conversion element.

  As an example of the basic configuration, the photoelectric conversion element includes a pair of electrodes and a photoelectric conversion film including a photoelectric conversion material of an organic material provided between the pair of electrodes. In the solid-state imaging device, a large number of photoelectric conversion elements having such a configuration are two-dimensionally arranged on a semiconductor substrate, charges are generated by photoelectric conversion in each photoelectric conversion film, and the charges generated in the photoelectric conversion film are a pair of electrodes. A signal corresponding to the electric charge moved to any one of the electrodes and moved to any one of the electrodes is read out by a CCD, a CMOS circuit or the like provided in the semiconductor substrate. In this specification, the photoelectric conversion film refers to a film that absorbs light having a specific wavelength incident thereon and generates charges (electrons and holes) corresponding to the absorbed light quantity.

  In recent years, development of a photoelectric conversion element capable of simultaneously obtaining images by visible light and infrared light has been advanced. Such a photoelectric conversion element has a configuration in which photoelectric conversion units capable of detecting different light wavelengths are stacked. When an inorganic material is used, it is difficult to absorb only infrared light alone, but since it can be designed to absorb only light in a specific wavelength range by using an organic material, infrared light can be used. An organic photoelectric conversion material is used for the photoelectric conversion film for detecting the above.

  Patent Document 1 describes a phthalocyanine dye having absorption in the infrared light region and having high photoelectric conversion performance in electrophotography, organic thin film solar cells, and the like.

  Non-Patent Document 1 reports the configuration of an organic solar cell containing a squarylium-based dye exhibiting high photoelectric conversion performance.

JP-A-63-186251 Applied Physics Letters, Vol. 29, No. 7, 1 October 1976, American Institute of Physics

However, when an attempt is made to produce a highly sensitive photoelectric conversion film that can absorb light in the infrared region, the exciton dissociation occurs in the layer made of a single organic material due to the electric field generated in the photoelectric conversion film. It was inevitable that the sensitivity would decrease.
One means for improving the exciton dissociation efficiency is to form a PN junction in a photoelectric conversion film containing an organic material. As the n-type organic semiconductor material, fullerene 60 and its derivatives are generally used. In this case, an IR material that absorbs infrared light generally has a shallow HOMO (maximum occupied molecular activation), and the LUMO (lowest unoccupied molecular orbital) from the HOMO of the IR material to the fullerene C60 at the interface between the IR material and fullerene C60. ) In the dark, the dark current increases.

  The present invention has been made in view of the above circumstances, and the object thereof is a photoelectric conversion material and a photoelectric conversion element that can sufficiently absorb light in the infrared region, have high sensitivity, and can reduce dark current. And providing a solid-state imaging device.

一般式（ＮＰ−１）

（式中、Ｍは金属原子を表す。Ｒ ₂₈ 、Ｒ ₂₉ は無くても良い。ある場合（＝軸配位子型）は、それぞれ独立に水素原子または置換基を表す。Ｒ ₄ 〜Ｒ ₂₇ はそれぞれ独立に水素原子または置換基を表す。）
（２）（１）に記載の光電変換材料であって、前記ナフタロシアニン化合物が、下記の一般式（ＮＰ−２）で示す軸配位子型の構造を有する光電変換材料。
一般式（ＮＰ−２）

（式中、ＭはＳｉ、Ｇｅ、Ｓｎのいずれかであり、Ｒ ¹ 〜Ｒ ²⁷ はそれぞれ独立に水素原子または置換基を表す。）
（３）（１）又は（２）に記載の光電変換材料を含む光電変換膜と、前記光電変換膜を挟んで対向する一対の電極とからなる第１光電変換部を備え、前記光電変換膜が前記ナフタロシアニン化合物からなる層と前記スクアリリウム化合物からなる層との積層構造を有する光電変換素子。
（４）（３）に記載の光電変換素子であって、前記光電変換膜に、前記ナフタロシアニン化合物と前記スクアリリウムとのバルクへテロ構造膜が形成されている光電変換素子。
（５）（３）又は（４）に記載の光電変換素子であって、前記スクアリリウム化合物からなる層の厚さが２０ｎｍ以下である光電変換素子。
（６）（３）から（５）のいずれかに記載の光電変換素子であって、前記第１光電変換部の吸収ピーク波長が６５０ｎｍ以上であり、かつ、波長域４００ｎｍ〜６００ｎｍの可視光を５０％以上透過する光電変換素子。
（７）（３）から（６）のいずれかに記載の光電変換素子であって、前記第１光電変換部が上方に積層された半導体基板を備え、可視域と赤外域を併せた範囲における吸収スペクトルの吸収ピークを可視域に持ち、吸収した光に応じた電荷を発生する第２光電変換部を前記半導体基板と前記第１光電変換部の間に少なくとも１つ備える光電変換素子。
（８）（７）に記載の光電変換素子であって、前記半導体基板が、前記第１光電変換部及び前記第２光電変換部の各々で発生した電荷を蓄積する蓄積部と、前記蓄積部に蓄積された電荷に応じた信号を読み出す信号読み出し部とを備える光電変換素子。
（９）（３）から（６）のいずれかに記載の光電変換素子であって、前記第１光電変換部が上方に積層された半導体基板を備え、可視域と赤外域を併せた範囲における吸収スペクトルの吸収ピークを可視域に持ち、吸収した光に応じた電荷を発生する第２光電変換部を前記半導体基板内に少なくとも１つ備える光電変換素子。
（１０）（９）に記載の光電変換素子であって、前記半導体基板が、前記第１光電変換部で発生した電荷を蓄積する蓄積部と、前記蓄積部に蓄積された電荷に応じた信号を読み出す信号読み出し部とを備える光電変換素子。
（１１）（７）又は（９）に記載の光電変換素子であって、前記第２光電変換部を複数備え、前記複数の第２光電変換部が、それぞれ異なる波長に吸収ピークを持つ光電変換素子。
（１２）
（１１）に記載の光電変換素子であって、前記複数の第２光電変換部が、前記第１光電変換部への光入射方向に積層されている光電変換素子。
（１３）（３）から（１０）に記載の光電変換素子であって、前記第２光電変換部を複数備え、前記複数の第２光電変換部が、それぞれ異なる波長に吸収ピークを持ち、且つ、前記第１光電変換部への光入射方向に対して垂直方向に配列されている光電変換素子。
（１４）（１２）又は（１３）に記載の光電変換素子であって、前記第２光電変換部を３つ備え、前記３つの第２光電変換部が、赤色の波長域の光を吸収するＲ光電変換部と、緑色の波長域の光を吸収するＧ光電変換部と、青色の波長域の光を吸収するＢ光電変換部である光電変換素子。
（１５）（３）から（１４）に記載の光電変換素子であって、前記第１光電変換部を透過した光が前記第２光電変換部に入射するように、前記光電変換部と前記第２光電変換部が平面視において重なっている光電変換素子。
（１６）（３）から（１５）に記載の光電変換素子であって、前記光電変換膜の上層及び下層のうち少なくとも一方に、前記電極からの電荷の注入を阻止する電荷ブロッキング層が設けられる光電変換素子。
（１７）（３）から（１６）に記載の光電変換素子であって、前記第１光電変換部の吸収ピーク波長が６５０ｎｍ以上であり、該吸収ピーク波長における吸収率が５０％以上である光電変換素子。
（１８）（７）,（９）,（１１）から（１５）のいずれかに記載の光電変換素子であって、前記第２光電変換部が波長域４００ｎｍ〜６００ｎｍの光の透過率が７５％以上である光電変換素子。
（１９）（３）から（１８）に記載の光電変換素子であって、前記一対の電極のうち少なくとも一方が、波長域４００ｎｍ〜９００ｎｍの光の透過率が９５％以上の導電性薄膜である光電変換素子。
（２０）（３）から（１８）に記載の光電変換素子であって、前記一対の電極のうち少なくとも一方が、波長域４００ｎｍ〜９００ｎｍの光の透過率が９５％以上の透明導電性薄膜である光電変換素子。
（２１）（３）から（２０）に記載の光電変換素子がアレイ状に配置された固体撮像素子。 The above object of the present invention is achieved by the following configurations.
(1) A photoelectric conversion material that generates a charge according to incident light, wherein the photoelectric conversion material is represented by a squarylium compound represented by the following general formula (1) and a general formula (NP-1) A photoelectric conversion material containing a naphthalocyanine compound.
General formula (1)

General formula (NP-1)

(In the formula, M represents a metal atom. R ₂₈ and R ₂₉ may be absent. In some cases (= axial ligand type), each independently represents a hydrogen atom or a substituent. R _{4 to} R _27. Each independently represents a hydrogen atom or a substituent.)
(2) The photoelectric conversion material according to (1), wherein the naphthalocyanine compound has an axial ligand type structure represented by the following general formula (NP-2).
General formula (NP-2)

(In the formula, M is any one of Si, Ge, and Sn, and R ^{1 to} R ²⁷ each independently represents a hydrogen atom or a substituent.)
(3) A photoelectric conversion film including the photoelectric conversion material according to (1) or (2) and a first photoelectric conversion unit including a pair of electrodes facing each other with the photoelectric conversion film interposed therebetween, and the photoelectric conversion film A photoelectric conversion element having a laminated structure of a layer made of the naphthalocyanine compound and a layer made of the squarylium compound.
(4) The photoelectric conversion element according to (3), wherein a bulk heterostructure film of the naphthalocyanine compound and the squarylium is formed on the photoelectric conversion film.
(5) The photoelectric conversion element according to (3) or (4), wherein the layer made of the squarylium compound has a thickness of 20 nm or less.
(6) The photoelectric conversion device according to any one of (3) to (5), wherein the first photoelectric conversion unit has an absorption peak wavelength of 650 nm or more, and visible light having a wavelength range of 400 nm to 600 nm. A photoelectric conversion element that transmits 50% or more.
(7) The photoelectric conversion element according to any one of (3) to (6), wherein the first photoelectric conversion unit includes a semiconductor substrate stacked above, and the visible region and the infrared region are combined. A photoelectric conversion element comprising at least one second photoelectric conversion unit having an absorption peak of an absorption spectrum in a visible region and generating a charge corresponding to absorbed light between the semiconductor substrate and the first photoelectric conversion unit.
(8) The photoelectric conversion element according to (7), wherein the semiconductor substrate accumulates charges generated in each of the first photoelectric conversion unit and the second photoelectric conversion unit, and the accumulation unit A photoelectric conversion element comprising: a signal reading unit that reads a signal corresponding to the charge accumulated in the signal.
(9) The photoelectric conversion element according to any one of (3) to (6), wherein the first photoelectric conversion unit includes a semiconductor substrate stacked above, and the visible region and the infrared region are combined. A photoelectric conversion element comprising at least one second photoelectric conversion unit in the semiconductor substrate that has an absorption peak of an absorption spectrum in a visible region and generates a charge corresponding to absorbed light.
(10) The photoelectric conversion element according to (9), wherein the semiconductor substrate accumulates charges generated in the first photoelectric conversion unit, and a signal corresponding to the charges accumulated in the accumulation unit A photoelectric conversion element comprising a signal reading unit for reading out.
(11) The photoelectric conversion element according to (7) or (9), comprising a plurality of the second photoelectric conversion units, wherein the plurality of second photoelectric conversion units each have an absorption peak at a different wavelength. element.
(12)
The photoelectric conversion element according to (11), wherein the plurality of second photoelectric conversion units are stacked in a light incident direction to the first photoelectric conversion unit.
(13) The photoelectric conversion element according to (3) to (10), including a plurality of the second photoelectric conversion units, wherein the plurality of second photoelectric conversion units have absorption peaks at different wavelengths, and The photoelectric conversion elements arranged in a direction perpendicular to the light incident direction to the first photoelectric conversion unit.
(14) The photoelectric conversion element according to (12) or (13), wherein the photoelectric conversion element includes three second photoelectric conversion units, and the three second photoelectric conversion units absorb light in a red wavelength region. A photoelectric conversion element that is an R photoelectric conversion unit, a G photoelectric conversion unit that absorbs light in the green wavelength range, and a B photoelectric conversion unit that absorbs light in the blue wavelength range.
(15) The photoelectric conversion element according to (3) to (14), wherein the photoelectric conversion unit and the first photoelectric conversion unit are arranged such that light transmitted through the first photoelectric conversion unit is incident on the second photoelectric conversion unit. 2 A photoelectric conversion element in which the photoelectric conversion units overlap in plan view.
(16) The photoelectric conversion element according to (3) to (15), wherein a charge blocking layer that prevents injection of charges from the electrode is provided in at least one of the upper layer and the lower layer of the photoelectric conversion film. Photoelectric conversion element.
(17) The photoelectric conversion device according to any one of (3) to (16), wherein the first photoelectric conversion unit has an absorption peak wavelength of 650 nm or more, and an absorptance at the absorption peak wavelength of 50% or more. Conversion element.
(18) The photoelectric conversion device according to any one of (7), (9), (11) to (15), wherein the second photoelectric conversion unit has a light transmittance of 75 to a wavelength region of 400 nm to 600 nm. % Photoelectric conversion element.
(19) The photoelectric conversion element according to (3) to (18), wherein at least one of the pair of electrodes is a conductive thin film having a light transmittance of 95% or more in a wavelength region of 400 nm to 900 nm. Photoelectric conversion element.
(20) The photoelectric conversion element according to (3) to (18), wherein at least one of the pair of electrodes is a transparent conductive thin film having a light transmittance of 95% or more in a wavelength region of 400 nm to 900 nm. A certain photoelectric conversion element.
(21) A solid-state imaging device in which the photoelectric conversion devices according to (3) to (20) are arranged in an array .

  According to the present invention, it is possible to provide a photoelectric conversion material, a photoelectric conversion element, and a solid-state imaging element that can sufficiently absorb light in the infrared region, have high sensitivity, and can reduce dark current.

  As a result of intensive studies, the inventors have found that the photosensitivity of the naphthalocyanine compound layer is improved when a bonding state of a layer made of a naphthalocyanine compound and a layer made of a squarylium compound is formed on the photoelectric conversion film. It was. As a cause of the sensitivity improvement, it is presumed that the dissociation efficiency of excitons generated in the naphthalocyanine compound layer is improved. The energy correlation of Ip (ionization energy) and Ea (electron affinity) of naphthalocyanine and squarylium used is a pn junction that promotes the phenomenon of exciton dissociation from the naphthalocyanine layer to the squarylium layer and charge transport. Since it is not sufficient to explain that the effect is a factor of this phenomenon, it is difficult to explain this phenomenon only from the existing pn-junction exciton dissociation mechanism. However, although the specific action is not completely clarified, as a result, the efficiency of dissociation of excitons generated in naphthalocyanine is promoted at the interface between naphthalocyanine and squarylium, and the positive action in squarylium. The hole is taken out and the photoelectric conversion performance is improved.

  When the photoelectric conversion material includes a naphthalocyanine compound and a squarylium compound, a phenomenon that dark current that frequently occurs when fullerene 60 is used as an n-type organic semiconductor material is less likely to occur. That is, when fullerene C60 is used, the dark current increases due to the discharge of dark charges from the IR material HOMO to fullerene C60LUMO, but squarylium has a high Ea (small Ea value), and naphthalocyanine. Spring carriers from HOMO to squarylium LUMO are unlikely to occur. In addition, even when squarylium is selected, a material, a thin film structure, and a high purity with a small amount of electric charge flowing out of a single substance can be selected, so that dark current can be prevented from increasing even if squarylium is introduced into the photoelectric conversion film.

The naphthalocyanine compound is represented by the following general formula.
General formula (NP-1)

M in the general formula (NP-1) represents a metal atom. The metal atom M is preferably Si (silicon), Ge (germanium), or Sn (tin). R ₂₈ and R ₂₉ may be omitted. In some cases (= axial ligand type), each independently represents a hydrogen atom or a substituent. R _{4 to} R ₂₇ each independently represents a hydrogen atom or a substituent. Examples of the substituent include an oxygen atom and a substituent W described later, and —O—R (R is a substituent), particularly a structure represented by the following general formula (NP-2) is preferable.

  In addition, in order to prevent impurities from being mixed and to make a more even and uniform laminated film, when depositing a material with strong crystallinity such as naphthalocyanine when depositing in vacuum by vapor deposition or the like, Since the interaction is too strong, it may not be vaporized by simple heating in a vacuum and film formation may not be possible. In this case, naphthalocyanine preferably has a structure having an axial ligand because vapor deposition is facilitated, and it is more preferable to have two or more axial ligands above and below the molecular plane. Furthermore, the introduction of the axial ligand makes it easier for the molecules to form a J-aggregate, so that it is possible to obtain a film structure that absorbs less visible light and has absorption in the infrared region (for solution absorption, The axial ligand is preferable also in this respect because the film after the formation has maximum absorption at a longer wavelength.

The structure of the axial ligand type of the naphthalocyanine compound is represented by the following general formula (NP-2).
General formula (NP-2)

In the general formula (NP-2), the metal atom M is any one of Si (silicon), Ge (germanium), and Sn (tin), and R ^{1 to} R ²⁷ each independently represent a hydrogen atom or a substituent. Here, the metal atom M is preferably Si. R ^{4 to} R ²⁷ are preferably all hydrogen atoms.

R ^{1 to} R ²⁷ represent a hydrogen atom or a substituent. Any of these substituents may be used, and examples thereof include the substituent W described later.

  In the present invention, when a specific moiety is referred to as a “group”, the moiety may be unsubstituted or substituted with one or more (up to the maximum possible) substituents. Means good. For example, “alkyl group” means a substituted or unsubstituted alkyl group. In addition, the substituent that can be used in the compound in the present invention may be any substituent.

As the substituent W, a halogen atom, an alkyl group (including a cycloalkyl group, a bicycloalkyl group, and a tricycloalkyl group), an alkenyl group (including a cycloalkenyl group and a bicycloalkenyl group), an alkynyl group, an aryl group, and a heterocyclic group (May be referred to as a heterocyclic group), cyano group, hydroxy group, nitro group, carboxy group, alkoxy group, aryloxy group, silyloxy group, heterocyclic oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, Aryloxycarbonyloxy group, amino group (including arylamino group), ammonio group, acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfamoylamino group, alkyl and arylsulfonyl Mino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo group, alkyl and arylsulfinyl group, alkyl and arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl group, carbamoyl group, Aryl and heterocyclic azo groups, imide groups, phosphino groups, phosphinyl groups, phosphinyloxy groups, phosphinylamino groups, phosphono groups, silyl groups, hydrazino groups, ureido groups, boronic acid groups (-B (OH) ₂ ), A phosphato group (—OPO (OH) ₂ ), a sulfato group (—OSO ₃ H), and other known substituents.

  More specifically, W represents the following (1) to (48).

(1) Halogen atom For example, fluorine atom, chlorine atom, bromine atom, iodine atom

(2) Alkyl group represents a linear, branched or cyclic substituted or unsubstituted alkyl group. They also include (2-a) to (2-e).

(2-a) alkyl group Preferably an alkyl group having 1 to 30 carbon atoms (for example, methyl, ethyl, n-propyl, isopropyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl, 2-cyanoethyl, 2-ethylhexyl) )

(2-b) cycloalkyl group Preferably, the substituted or unsubstituted cycloalkyl group having 3 to 30 carbon atoms (for example, cyclohexyl, cyclopentyl, 4-n-dodecylcyclohexyl).

(2-c) Bicycloalkyl group Preferably, the substituted or unsubstituted bicycloalkyl group having 5 to 30 carbon atoms (for example, bicyclo [1,2,2] heptan-2-yl, bicyclo [2,2,2] Octane-3-yl)

(2-d) Tricycloalkyl group Preferably, it is a substituted or unsubstituted tricycloalkyl group having 7 to 30 carbon atoms (for example, 1-adamantyl).

(2-e) A polycyclic cycloalkyl group having a larger ring structure In addition, an alkyl group (for example, an alkyl group of an alkylthio group) in a substituent described below represents an alkyl group of such a concept, Group and alkynyl group.

(3) Alkenyl group represents a linear, branched, or cyclic substituted or unsubstituted alkenyl group. They include (3-a) to (3-c).

(3-a) Alkenyl group Preferably it is a C2-C30 substituted or unsubstituted alkenyl group (for example, vinyl, allyl, prenyl, geranyl, oleyl).

(3-b) Cycloalkenyl group Preferably, the substituted or unsubstituted cycloalkenyl group having 3 to 30 carbon atoms (for example, 2-cyclopenten-1-yl, 2-cyclohexen-1-yl)

(3-c) Bicycloalkenyl group A substituted or unsubstituted bicycloalkenyl group, preferably a substituted or unsubstituted bicycloalkenyl group having 5 to 30 carbon atoms (for example, bicyclo [2,2,1] hept-2-ene -1-yl, bicyclo [2,2,2] oct-2-en-4-yl)

(4) Alkynyl group Preferably, the substituted or unsubstituted alkynyl group having 2 to 30 carbon atoms (for example, ethynyl, propargyl, trimethylsilylethynyl group)

(5) Aryl group Preferably, it is a C6-C30 substituted or unsubstituted aryl group (for example, phenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecanoylaminophenyl, ferrocenyl).

(6) Heterocyclic group Preferably, it is a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered substituted or unsubstituted aromatic or non-aromatic heterocyclic compound, more preferably carbon. It is a 5- or 6-membered aromatic heterocyclic group of 2 to 50.
(For example, 2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl. In addition, a cationic heterocyclic group such as 1-methyl-2-pyridinio and 1-methyl-2-quinolinio may be used)

(7) Cyano group

(8) Hydroxy group

(9) Nitro group

(10) Carboxy group

(11) Alkoxy group Preferably, the substituted or unsubstituted alkoxy group having 1 to 30 carbon atoms (for example, methoxy, ethoxy, isopropoxy, t-butoxy, n-octyloxy, 2-methoxyethoxy)

(12) Aryloxy group Preferably, the substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms (for example, phenoxy, 2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy, 2-tetradecanoyl) Aminophenoxy)

(13) Silyloxy group Preferably, the silyloxy group having 3 to 20 carbon atoms (for example, trimethylsilyloxy, t-butyldimethylsilyloxy)

(14) Heterocyclic oxy group Preferably, the substituted or unsubstituted heterocyclic oxy group having 2 to 30 carbon atoms (for example, 1-phenyltetrazol-5-oxy, 2-tetrahydropyranyloxy)

(15) Acyloxy group, preferably a formyloxy group, a substituted or unsubstituted alkylcarbonyloxy group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyloxy group having 6 to 30 carbon atoms (for example, formyloxy, acetyloxy , Pivaloyloxy, stearoyloxy, benzoyloxy, p-methoxyphenylcarbonyloxy)

(16) Carbamoyloxy group Preferably, the substituted or unsubstituted carbamoyloxy group having 1 to 30 carbon atoms (for example, N, N-dimethylcarbamoyloxy, N, N-diethylcarbamoyloxy, morpholinocarbonyloxy, N, N- Di-n-octylaminocarbonyloxy, Nn-octylcarbamoyloxy)

(17) Alkoxycarbonyloxy group Preferably, the substituted or unsubstituted alkoxycarbonyloxy group having 2 to 30 carbon atoms (for example, methoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy, n-octylcarbonyloxy)

(18) Aryloxycarbonyloxy group Preferably, the substituted or unsubstituted aryloxycarbonyloxy group having 7 to 30 carbon atoms (for example, phenoxycarbonyloxy, p-methoxyphenoxycarbonyloxy, pn-hexadecyloxyphenoxycarbonyl) Oxy)

(19) Amino group Preferably, an amino group, a substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 30 carbon atoms (for example, amino, methylamino, dimethylamino) Anilino, N-methyl-anilino, diphenylamino)

(20) Ammonio group Preferably, an ammonio group, an ammonio group substituted with 1 to 30 carbon atoms or an unsubstituted alkyl, aryl, or heterocyclic ring (for example, trimethylammonio, triethylammonio, diphenylmethylammonio)

(21) Acylamino group Preferably, a formylamino group, a substituted or unsubstituted alkylcarbonylamino group having 1 to 30 carbon atoms, a substituted or unsubstituted arylcarbonylamino group having 6 to 30 carbon atoms (for example, formylamino, acetyl) Amino, pivaloylamino, lauroylamino, benzoylamino, 3,4,5-tri-n-octyloxyphenylcarbonylamino)

(22) Aminocarbonylamino group Preferably, the substituted or unsubstituted aminocarbonylamino having 1 to 30 carbon atoms (for example, carbamoylamino, N, N-dimethylaminocarbonylamino, N, N-diethylaminocarbonylamino, morpholinocarbonylamino) )

(23) Alkoxycarbonylamino group Preferably, the substituted or unsubstituted alkoxycarbonylamino group having 2 to 30 carbon atoms (for example, methoxycarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino, n-octadecyloxycarbonylamino, N- Methyl-methoxycarbonylamino)

(24) Aryloxycarbonylamino group Preferably, the substituted or unsubstituted aryloxycarbonylamino group having 7 to 30 carbon atoms (for example, phenoxycarbonylamino, p-chlorophenoxycarbonylamino, mn-octyloxyphenoxycarbonylamino) )

(25) Sulfamoylamino group Preferably, the substituted or unsubstituted sulfamoylamino group having 0 to 30 carbon atoms (for example, sulfamoylamino, N, N-dimethylaminosulfonylamino, Nn-octylamino) Sulfonylamino)

(26) Alkyl or arylsulfonylamino group Preferably, the substituted or unsubstituted alkylsulfonylamino having 1 to 30 carbon atoms, or the substituted or unsubstituted arylsulfonylamino having 6 to 30 carbon atoms (for example, methylsulfonylamino, butylsulfonyl) Amino, phenylsulfonylamino, 2,3,5-trichlorophenylsulfonylamino, p-methylphenylsulfonylamino)

(27) Mercapto group

(28) Alkylthio group Preferably, it is a C1-C30 substituted or unsubstituted alkylthio group (for example, methylthio, ethylthio, n-hexadecylthio).

(29) Arylthio group Preferably, the substituted or unsubstituted arylthio having 6 to 30 carbon atoms (for example, phenylthio, p-chlorophenylthio, m-methoxyphenylthio)

(30) Heterocyclic thio group Preferably, the substituted or unsubstituted heterocyclic thio group having 2 to 30 carbon atoms (for example, 2-benzothiazolylthio, 1-phenyltetrazol-5-ylthio)

(31) Sulfamoyl group Preferably, the substituted or unsubstituted sulfamoyl group having 0 to 30 carbon atoms (for example, N-ethylsulfamoyl, N- (3-dodecyloxypropyl) sulfamoyl, N, N-dimethylsulfamoyl) N-acetylsulfamoyl, N-benzoylsulfamoyl, N- (N′-phenylcarbamoyl) sulfamoyl)

(32) Sulfo group

(33) an alkyl or arylsulfinyl group, preferably a substituted or unsubstituted alkylsulfinyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfinyl group having 6 to 30 carbon atoms (for example, methylsulfinyl, ethylsulfinyl, phenylsulfinyl, p-methylphenylsulfinyl)

(34) an alkyl or arylsulfonyl group, preferably a substituted or unsubstituted alkylsulfonyl group having 1 to 30 carbon atoms, a substituted or unsubstituted arylsulfonyl group having 6 to 30 carbon atoms, such as methylsulfonyl, ethylsulfonyl, phenylsulfonyl, p-methylphenylsulfonyl)

(35) Acyl group Preferably, it is a formyl group, a substituted or unsubstituted alkylcarbonyl group having 2 to 30 carbon atoms, a substituted or unsubstituted arylcarbonyl group having 7 to 30 carbon atoms, a substituted or unsubstituted group having 4 to 30 carbon atoms. Heterocyclic carbonyl groups bonded to carbonyl groups at substituted carbon atoms (eg, acetyl, pivaloyl, 2-chloroacetyl, stearoyl, benzoyl, pn-octyloxyphenylcarbonyl, 2-pyridylcarbonyl, 2-furylcarbonyl )

(36) Aryloxycarbonyl group Preferably, it is a substituted or unsubstituted aryloxycarbonyl group having 7 to 30 carbon atoms (for example, phenoxycarbonyl, o-chlorophenoxycarbonyl, m-nitrophenoxycarbonyl, pt-butylphenoxycarbonyl). )

(37) Alkoxycarbonyl group Preferably, the substituted or unsubstituted alkoxycarbonyl group having 2 to 30 carbon atoms (for example, methoxycarbonyl, ethoxycarbonyl, t-butoxycarbonyl, n-octadecyloxycarbonyl)

(38) Carbamoyl group Preferably, the substituted or unsubstituted carbamoyl having 1 to 30 carbon atoms (for example, carbamoyl, N-methylcarbamoyl, N, N-dimethylcarbamoyl, N, N-di-n-octylcarbamoyl, N- (Methylsulfonyl) carbamoyl)

(39) Aryl and heterocyclic azo group Preferably, the substituted or unsubstituted arylazo group having 6 to 30 carbon atoms, or the substituted or unsubstituted heterocyclic azo group having 3 to 30 carbon atoms (for example, phenylazo, p-chlorophenylazo , 5-ethylthio-1,3,4-thiadiazol-2-ylazo)

(40) Imido group, preferably N-succinimide, N-phthalimide

(41) Phosphino group Preferably, the substituted or unsubstituted phosphino group having 2 to 30 carbon atoms (for example, dimethylphosphino, diphenylphosphino, methylphenoxyphosphino)

(42) Phosphinyl group Preferably, the substituted or unsubstituted phosphinyl group having 2 to 30 carbon atoms (for example, phosphinyl, dioctyloxyphosphinyl, diethoxyphosphinyl).

(43) Phosphinyloxy group Preferably, the substituted or unsubstituted phosphinyloxy group having 2 to 30 carbon atoms (for example, diphenoxyphosphinyloxy, dioctyloxyphosphinyloxy)

(44) Phosphinylamino group Preferably, the substituted or unsubstituted phosphinylamino group having 2 to 30 carbon atoms (for example, dimethoxyphosphinylamino, dimethylaminophosphinylamino)

(45) Phosphor group

(46) Silyl group Preferably, the substituted or unsubstituted silyl group having 3 to 30 carbon atoms (for example, trimethylsilyl, triethylsilyl, triisopropylsilyl, t-butyldimethylsilyl, phenyldimethylsilyl)

(47) Hydrazino group Preferably a substituted or unsubstituted hydrazino group having 0 to 30 carbon atoms (for example, trimethylhydrazino)

(48) Ureido group Preferably, the substituted or unsubstituted ureido group having 0 to 30 carbon atoms (for example, N, N-dimethylureido)

  Two Ws can also form a ring together. Examples of such a ring include an aromatic or non-aromatic hydrocarbon ring, a heterocyclic ring, and a polycyclic fused ring formed by further combining them. For example, benzene ring, naphthalene ring, anthracene ring, phenanthrene ring, fluorene ring, triphenylene ring, naphthacene ring, biphenyl ring, pyrrole ring, furan ring, thiophene ring, imidazole ring, oxazole ring, thiazole ring, pyridine ring, pyrazine ring, Pyrimidine ring, pyridazine ring, indolizine ring, indole ring, benzofuran ring, benzothiophene ring, isobenzofuran ring, quinolidine ring, quinoline ring, phthalazine ring, naphthyridine ring, quinoxaline ring, quinoxazoline ring, isoquinoline ring, carbazole ring, phenant Examples include lysine ring, acridine ring, phenanthroline ring, thianthrene ring, chromene ring, xanthene ring, phenoxathiin ring, phenothiazine ring, and phenazine ring.

Among the above-described substituents W, those having a hydrogen atom may be substituted with the above groups by removing this. Examples of such substituents, -CONHSO ₂ - group (sulfonylcarbamoyl group, a carbonyl sulfamoyl group), - CONHCO- group (carbonylation carbamoyl group), - SO ₂ NHSO ₂ - group (sulfonylsulfamoyl group ). More specifically, alkylcarbonylaminosulfonyl group (for example, acetylaminosulfonyl), arylcarbonylaminosulfonyl group (for example, benzoylaminosulfonyl group), alkylsulfonylaminocarbonyl group (for example, methylsulfonylaminocarbonyl), arylsulfonylamino A carbonyl group (for example, p-methylphenylsulfonylaminocarbonyl) is mentioned.

Of R ^{4 to} R ²⁷ , 8 or more are preferably hydrogen atoms, more preferably 16 or more are hydrogen atoms, and most preferably all are hydrogen atoms. The substituent for R ^{4 to} R ²⁷ is preferably selected from a linear or branched alkyl group having 1 to 6 carbon atoms, and includes a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, More preferably, it is selected from any of t-butyl groups. Two or more R ^{4 to} R ²⁷ may jointly form a ring, in particular, R ⁶ and R ⁷ , R ¹² and R ¹³ , R ¹⁸ and R ¹⁹ , R ²⁴ and R ²⁵ And forming a benzene ring.

R ^{1 to} R ³ may be each independently a linear alkyl group, but in this case, if it is too long, it is easy to decompose during vapor deposition, and therefore it is preferably a C 3-6 linear alkyl group. Further, from the viewpoint of moderately weakening the intermolecular interaction and improving the deposition property, at least one of R ^{1 to} R ³ is preferably a branched alkyl group, more preferably 3 to 6 carbon atoms. It is a branched alkyl group, and more preferably an i-propyl group, i-Bu group, s-Bu group, or t-Bu group. Moreover, it is also preferable that at least one of R ^{1 to} R ³ is an alkoxy group, more preferably an alkoxy group having 1 to 6 carbon atoms, and still more preferably a methoxy group, an ethoxy group, an n-propoxy group, i -A propoxy group, an n-butoxy group, or a t-butoxy group. It is also preferable that at least one of R ^{1 to} R ³ is an aromatic hydrocarbon group or an aromatic heterocyclic group, more preferably an aromatic hydrocarbon group having 2 to 12 carbon atoms or an aromatic hetero group. A cyclic group, more preferably a phenyl group, a naphthyl group, a pyridyl group, a quinolinyl group, or a thiophenyl group, and particularly preferably a substituted or unsubstituted phenyl group. It is also preferred that R ^{1 to} R ³ are selected from two or more different substituents. In this case, any two or more different substituents may be used, but at least one of them is a linear or branched alkyl group ( Preferably those having 1 to 8 carbon atoms, more preferably those having 1 to 4 carbon atoms), alkoxy groups (preferably those having 1 to 8 carbon atoms, more preferably those having 1 to 4 carbon atoms), aromatic carbonization It is preferably either a hydrogen group or an aromatic heterocyclic group (preferably having 2 to 12 carbon atoms, more preferably having 2 to 10 carbon atoms), and at least two are selected from these groups Is more preferable, and it is particularly preferable that all three are selected from these.

  The center metal M is particularly preferably Si.

  Specific examples of the compound of the present invention are shown below, but the present invention is not limited to the following examples.

(Synthesis method)
The naphthalocyanine ring formation reaction of the compound of the present invention is described in the following paragraphs. This can be carried out according to pages 29 to 77 of “Phthalocyanine as a functional dye” edited by Eiko Okumura (IPC, 2004).

  Representative methods for synthesizing naphthalocyanine derivatives include the Weiler method, phthalonitrile method, lithium method, subphthalocyanine method, and chlorinated phthalocyanine method described in these documents. Any reaction conditions may be used in the naphthalocyanine ring formation reaction of the present invention. In the ring formation reaction, it is preferable to add various metals to be the central metal of naphthalocyanine, but a desired metal may be introduced after the synthesis of a naphthalocyanine derivative having no central metal. Any solvent may be used as the reaction solvent, but a solvent having a high boiling point is preferable. In order to promote the ring formation reaction, it is preferable to use an acid or a base, and it is particularly preferable to use a base. Optimum reaction conditions vary depending on the structure of the target naphthalocyanine derivative, but can be set with reference to specific reaction conditions described in the above-mentioned documents.

  As raw materials used for the synthesis of the above naphthalocyanine derivatives, derivatives such as naphthalic anhydride, naphthalimide, naphthalic acid and salts thereof, naphthalic acid diamide, naphthalonitrile, 1,3-diiminobenzoisoindoline should be used. Can do. These raw materials may be synthesized by any known method.

(Synthesis example)
[Synthesis of Compound 2]

  Mix silicon dihydroxynaphthalocyanine (1.0 g, 1.29 mmol), chlorotriisobutylsilane (4.4 mL), tributylamine (4.0 mL), and β-picoline (140 mL) and heat under nitrogen atmosphere for 2 hours Refluxed. The reaction solution was cooled to room temperature, and then poured into a mixed solvent of water (100 mL) / ethanol (100 mL) to precipitate a green powder. After thoroughly washing with ethanol, the origin component was removed by column chromatography (NH silica, developing solvent toluene) and recrystallized from toluene to give Compound 3 (0.82 g, 54% yield) as a metallic glossy green crystal. ) It was confirmed by HPLC measurement that the obtained compound 3 had a purity of 99% or more.

¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.12 (s, 8H), 8.68 (dd, 8H), 7.93 (dd, 8H), −0.40 (d, 36H), −0 .49 to -0.60 (m, 6H), -2.00 ppm (d, 12H).

[Synthesis of other compounds]
According to the synthesis method of Compound 2, Compound 1, Compound 3, Compound 4, Compound 5, Compound 6, Compound 8, Compound 8, Compound 9, Compound 10, Compound 11, Compound 12, Compound 13, and Compound 14 were synthesized. ¹ H NMR measurement results are shown below.

[Compound 1]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.12 (s, 8H), 8.68 (dd, 8H), 7.94 (dd, 8H), −0.90 (d, 36H), −1 .60 to -1.70 ppm (q, 6H).

[Compound 3]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 9.92 (s, 8H), 8.68 (dd, 8H), 7.96 (dd, 8H), 6.59 (dd, 6H), 6.24 (Dd, 12H), 5.13 ppm (d, 12H).

[Compound 4]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.12 (s, 8H), 8.67 (dd, 8H), 7.94 (dd, 8H), 1.60 (q, 12H), −0. 19 ppm (t, 18H).

[Compound 5]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.12 (s, 8H), 8.67 (dd, 8H), 7.94 (dd, 8H), −0.22 ppm (s, 54H).

[Compound 6]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.12 (s, 8H), 8.67 (dd, 8H), 7.94 (dd, 8H), 1.72 to 1.50 (m, 6H) , 0.60 to 0.42 (m, 6H), 0.20 to 0.11 (m, 12H), 0.11 to -0.08 (m, 36H), -0.38 to -0.49 (M, 18H).

[Compound 8]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.12 (s, 8H), 8.68 (dd, 8H), 7.94 (dd, 8H), −0.91 (s, 18H), −1 .82 ppm (s, 12H).

[Compound 9]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.14 (s, 8H), 8.69 (dd, 8H), 7.94 (dd, 8H), −0.59 to −0.69 (q, 2H), -0.84 (d, 12H), -1.22 (s, 12H), -2.58 ppm (s, 12H).

[Compound 10]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.12 (s, 8H), 8.67 (dd, 8H), 7.93 (dd, 8H), 1.10 to 0.97 (m, 4H) , 0.86 to 0.70 (m, 10H). 0.69 to 0.57 (m, 4H), 0.32 to 0.09 (m, 8H), -0.64 to -0.79 (m, 4H), -0.95 to -1.11 (M, 24H), -1.59 to -1.74 (m, 4H), -2.09 to -2.21 ppm (m, 4H).

[Compound 11]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.13 (s, 8H), 8.68 (dd, 8H), 7.94 (dd, 8H), 0.90 to 0.80 (m, 2H) , 0.60 to 0.49 (m, 4H), 0.10 to -0.12 (m, 8H), -0.53 to 0.63 (m, 2H), -1.31 to -1. 50 (m, 4H), -1.80 to -1.95 (m, 2H), -2.59 ppm (s, 12H).

[Compound 12]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.07 (s, 8H), 8.62 (dd, 8H), 7.95 (dd, 8H), 6.59 (dd, 6H), 6.24 (Dd, 12H), 5.13 (d, 12H), -2.22 ppm (s, 12H).

[Compound 13]
¹ H NMR (CDCl ₃ , 400 MHz) δ = 10.07 (s, 8H), 8.62 (dd, 8H), 7.95 (dd, 8H), −2.00 ppm (s, 12H).

[Compound 14]
δ = 10.12 (s, 8H), 8.68 (dd, 8H), 7.94 (dd, 8H), 0.92 (t, 4H), -0.58 to -0.72 (m, 4H), -1,68--1.80 (m, 4H), -2.47 ppm (s, 12H).

In Compound 8, Compound 9, Compound 10, Compound 11, etc., a dimer as shown in the following general formula (NP-3) is by-produced. In this case, δ = 9 in ¹ H NMR (CDCl ₃ , 400 MHz). Signals derived from the dimer are detected at .4 (s), 9.0 (dd), and 8.3 (dd), but can be removed by a method such as sublimation purification.
General formula (NP-3)

In the general formula (NP-3), the metal atom M is any one of Si, Ge, and Sn, and R _{1 to} R ₃ each represent a substituent other than a hydrogen atom. However, all of R _{1 to} R ₃ do not become the same linear alkyl group.

Next, the squarylium compound represented by the general formula (SQ-1) will be described.
General formula (SQ-1)

The substituent represented by A and B in the general formula (SQ-1) may be any substituent as long as the bonding position is sp ² carbon. Examples of the substituent include a group comprising an aryl group or a heterocyclic group. Examples of the substituent are preferably an aryl group, a heterocyclic group (which may be referred to as a heterocyclic group), or a methine group to which an aryl group or a heterocyclic group is bonded, and the heterocyclic carbon atom of the heterocyclic group and The case where the methine group is couple | bonded is preferable. The aryl group is preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and examples thereof include phenyl, p-tolyl, naphthyl, m-chlorophenyl, o-hexadecanoylaminophenyl, and ferrocenyl. Can do. The heterocyclic group is preferably a monovalent group obtained by removing one hydrogen atom from a 5- or 6-membered, substituted or unsubstituted, aromatic or non-aromatic heterocyclic compound, and more preferably carbon. It is a 5- or 6-membered aromatic heterocyclic group of the number 2 to 30. For example, 2-furyl, 2-thienyl, 2-pyrimidinyl, 2-benzothiazolyl and the like can be mentioned. A cationic heterocyclic group such as 1-methyl-2-pyridinio and 1-methyl-2-quinolinio may also be used. In the case of a methine group to which an aryl group or a heterocyclic group is bonded, the above-mentioned ones are preferably used as the aryl group or the heterocyclic group, and the heterocyclic group includes a 2-cyclobutene-1,3-dione nucleus. An example thereof is a 2-cyclobutene-1,3-dione nucleus bonded to a methine group to which a heterocyclic group (for example, an indolenine nucleus) is bonded. The methine group is a substituted or unsubstituted methine group, and examples of the substituent of the methine group include the above-described substituent W, and an alkyl group (preferably a substituted or unsubstituted alkyl group having 1 to 5 carbon atoms, For example, methyl, ethyl, propyl, butyl, benzyl, phenethyl), an aryl group (preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, such as phenyl, p-tolyl, naphthyl) and the like are preferable. In the case of a methine group bonded to a heterocyclic group, a methine group bonded to a carbon atom in the heterocyclic ring is preferred.
When the compound represented by the general formula (SQ-1) is used for infrared absorption, one of A and B is a methine group to which an indolenine nucleus (preferably bonded at the 2-position of the indolenine nucleus) is bound. A compound in which the other is a methine group to which a quinoline nucleus (preferably bonded at the 2-position or 4-position of the quinoline nucleus, more preferably at the 2-position) is bonded is preferable. In the present specification, when at least one of A and B is a methine group to which an indolenine nucleus is bonded, the substituent is referred to as an indolenine type substituent.

In the present invention, the compound represented by General Formula (SQ-1) is preferably a compound selected from General Formula (SQ-2).
General formula (SQ-2)

As a substituent represented by R < ¹ > -R < ⁸ > of general formula (SQ-2), what kind of thing may be sufficient, but the above-mentioned W is mentioned, for example. R ¹ is preferably a hydrogen atom, a methyl group, or a phenyl group, more preferably a hydrogen atom or a methyl group. R ² is preferably an alkyl group (methyl, ethyl, etc.) or a phenyl group, more preferably a methyl group. R ³ and R ⁴ are preferably each independently an alkyl group (methyl, ethyl, propyl, butyl, etc.) or a phenyl group, more preferably a methyl group. R ^{5 to} R ⁸ are preferably all hydrogen atoms, or R ⁵ and R ⁶ , R ⁶ and R ⁷ , R ⁷ and R ⁸ are benzo-fused, and the remainder is a hydrogen atom. More preferably, all are hydrogen atoms.
B has the same meaning as in the general formula SQ-1, but for infrared absorption, it may be an unsubstituted methine group to which a quinoline nucleus, a pyrylium nucleus, a thiopyrylium nucleus, an azulene nucleus, and a dihydroperimidine nucleus are bonded. Preferably, it is an unsubstituted methine group to which a quinoline nucleus is bonded, and a preferable bonding position is the same as in the case of the general formula (SQ-1).

In the present invention, the compound represented by General Formula (SQ-2) is preferably a compound selected from General Formula (SQ-3).
General formula (SQ-3)

In General Formula (SQ-3), B has the same meaning as in General Formula SQ-1, and the preferred range is also the same.
In particular, the indolenine nucleus structure bonded to the methine group in the general formula (SQ-3) is important, and this structure is considered to have the effect of improving the photoelectric conversion efficiency, lowering the deposition temperature, and raising the decomposition temperature. . From the viewpoint of vapor deposition properties, a simple indolenine structure such as the general formula (SQ-3) is preferred which has a low molecular weight for reducing the vapor deposition temperature and does not introduce a group for increasing the decomposability.
In order to increase the absorption wavelength for infrared absorption, the structure of the substituent B is important. However, even those that exhibit long-wave absorption are inappropriate because of high decomposability because the vapor deposition performance is reduced. About the ease of decomposition | disassembly of each substituent, when the both ends of general formula (SQ-1) are made into the same substituent (A = B), it is preferable that it is 200 degreeC or more.
Examples of the compounds represented by the general formulas (SQ-1), (SQ-2), and (SQ-3) used in the present invention are shown below. However, the present invention is not limited to the following examples.

  The compounds represented by the above general formulas (SQ-1), (SQ-2) and (SQ-3) and the specific example compounds are represented by one chemical formula. Therefore, it is needless to say that those represented by other indications are also included in the present invention.

  The compounds shown in the above specific examples can be synthesized with reference to known literature (Dyes and Pigments, 21 (1993), 227-234, etc.).

A photoelectric conversion element including a photoelectric conversion part including a photoelectric conversion film containing the compounds represented by the general formulas (SQ-1), (SQ-2), and (SQ-3) as an organic photoelectric conversion material will be described.
Hereinafter, embodiments of the photoelectric conversion element of the present invention will be described with reference to the drawings. In the following description, light in the red (R) wavelength region (R light) generally indicates light in the wavelength range of 550 to 650 nm, and light in the green (G) wavelength region (G light) Generally indicates light in the wavelength range of 450 to 610 nm, blue (B) wavelength light (B light) generally indicates light in the wavelength range of 400 to 520 nm, and in the infrared range Light in the wavelength range (infrared light) generally indicates light in the wavelength range of 680 to 10000 nm, and light in the visible wavelength range (visible light) generally has a wavelength in the range of 400 to 650 nm. Show light.

(First Embodiment of Photoelectric Conversion Element)
FIG. 1 is a schematic cross-sectional view showing a schematic configuration of the photoelectric conversion element according to the first embodiment of the present invention.
1 includes a lower electrode 11, an upper electrode 13 facing the lower electrode 11, and a photoelectric conversion film 12 provided between the lower electrode 11 and the upper electrode 13. At least. The photoelectric conversion element shown in FIG. 1 is used with light incident from above the upper electrode 13. It is preferable that the lower electrode 11 and the upper electrode 13 constitute a pair of electrodes, and at least one of the pair of electrodes is a conductive thin film having a light transmittance of 95% or more in a wavelength region of 400 nm to 900 nm. Alternatively, at least one of the pair of electrodes is preferably a transparent conductive thin film having a light transmittance of 95% or more in a wavelength region of 400 nm to 900 nm.

The upper electrode 13 of this embodiment is a transparent material made of a conductive material that is transparent to light (visible light and infrared light) in a range that combines the visible range and the infrared range (for example, a range of wavelengths of 400 nm or more). Electrode. In this specification, “transparent to light of a certain wavelength” means that 70% or more of light of that wavelength is transmitted. A bias voltage is applied to the upper electrode 13 by a wiring (not shown). The polarity of the bias voltage is determined so that, of the charges generated in the photoelectric conversion film 12, electrons move to the upper electrode 13 and holes move to the lower electrode 11. Of course, the bias voltage may be set so that, of the charges generated in the photoelectric conversion film 12, holes move to the upper electrode 13 and electrons move to the lower electrode 11. Further, the bias voltage is obtained by dividing the value by the distance between the lower electrode 11 and the upper electrode 13 so as to be between 1.0 × 10 ⁵ V / cm and 1.0 × 10 ⁷ V / cm. Preferably, it is between 1.0 × 10 ⁴ V / cm and 1.0 × 10 ⁶ V / cm. With this bias voltage, it is possible to efficiently move charges to the upper electrode 13 and to extract a signal corresponding to the charges to the outside.

  Since the lower electrode 11 is applied to a solid-state imaging device (hereinafter referred to as a visible / infrared imaging device) capable of simultaneously capturing a visible image and capturing an infrared image, the lower electrode 11 also includes a portion of incident light below it. Therefore, it is desirable to use a transparent electrode in the same manner as the upper electrode 13. However, the lower electrode 11 does not have to be transparent to light in the infrared region, and may be transparent to at least light in the visible region.

  The photoelectric conversion film 12 has an absorption peak of an absorption spectrum in a range including a visible region and an infrared region (light having a wavelength of 400 nm or more) in the infrared region, and generates an electric charge corresponding to the absorbed infrared light. It is the film | membrane comprised including.

  As such an organic photoelectric conversion material, a material containing the above-described naphthalocyanine compound and squaryu compound is preferably used. Here, the photoelectric conversion material is preferably a naphthalocyanine compound having an axial ligand type structure.

  The photoelectric conversion film 12 preferably has a stacked structure of a layer made of a naphthalocyanine compound and a layer made of a squarylium compound. The photoelectric conversion film 12 is preferably formed with a bulk heterostructure film of a naphthalocyanine compound and squarylium. Furthermore, the thickness of the layer made of the squarylium compound is preferably 20 nm or less.

In order to apply the photoelectric conversion element including the photoelectric conversion part A configured as described above to the visible / infrared imaging element, the photoelectric conversion part A has the photoelectric conversion film 12 to obtain information other than human visibility. The wavelength of the absorption peak in the infrared region of the organic photoelectric conversion material contained is preferably 650 nm or more (preferably 700 nm or more), and the absorptance at that wavelength is preferably 50% or more, more preferably 80% or more. is there. Further, in order to sufficiently obtain a visible light signal below the photoelectric conversion unit A, the photoelectric conversion unit A preferably transmits 50% or more of visible light as a whole, and more preferably 75% or more. The visible light transmittance of the photoelectric conversion part A can be adjusted by appropriately selecting the constituent materials and the thicknesses of the upper electrode 13, the lower electrode 11, and the photoelectric conversion film 12.
In the present invention, “absorptivity and transmittance in a certain wavelength region α to β nm” means “in the wavelength region α to β nm, when the absorptivity and transmittance are 100%”. The integral value of X can be expressed as Y / X × 100, where X is the absorptance of each wavelength, and Y is the integral value in the wavelength range α to β nm of the transmittance.

  The light transmittance of the lower electrode 11 and the upper electrode 13 greatly influences the infrared light absorption rate and the visible light absorption rate of the lower layer. When incident light is absorbed and reflected by the lower electrode 11 and the upper electrode 13, the absolute amount of light reaching the lower layer is reduced, which directly leads to a reduction in sensitivity. Therefore, in order to transmit more light to the lower layer and increase the sensitivity in the photoelectric conversion film 12, the transmittance of visible light and infrared light of the upper electrode 13 is preferably 90% or more, more preferably 95. % Or more. Moreover, in order to transmit more visible light to the lower layer and increase the sensitivity of the visible light detection element provided below the photoelectric conversion element, the visible light transmittance of the lower electrode 11 is preferably 90% or more. Preferably it is 95% or more.

As a material of the lower electrode 11 and the upper electrode 13 satisfying such conditions, a transparent conductive oxide (TCO) having a high transmittance for visible light and infrared light and a small resistance value is preferably used. Can do. A metal thin film such as Au can also be used. However, if an attempt is made to obtain a transmittance of 90% or more, the resistance value increases drastically, so TCO is preferable. As TCO, in particular, can be ITO, IZO, AZO, FTO, it is preferably used SnO _2, TiO _2, ZnO ₂ and the like.

  When a transparent conductive material such as TCO is formed on the photoelectric conversion film 12 to form the upper electrode 13, a DC short circuit or an increase in leakage current may occur. One reason for this is considered to be that fine cracks introduced into the photoelectric conversion film 12 are covered by a dense film such as TCO, and conduction between the transparent conductive material film on the opposite side is increased. Therefore, in the case of an electrode having a poor film quality such as Al (aluminum), an increase in leakage current hardly occurs. By controlling the film thickness of the transparent conductive material film with respect to the thickness of the photoelectric conversion film 12 (that is, the depth of cracks), an increase in leakage current can be largely suppressed. The thickness of the transparent conductive material film, that is, the thickness of the upper electrode 13 is desirably 1/5 or less, preferably 1/10 or less of the thickness of the photoelectric conversion film 12.

  Usually, when the transparent conductive material film is made thinner than a certain range, the resistance value is rapidly increased. However, in the photoelectric conversion element of the present invention, the sheet resistance is preferably 100 to 10,000 Ω / □ and can be thinned. The degree of freedom in the film thickness range is large. In addition, the thinner the transparent conductive material film is, the less light is absorbed, and the light transmittance is generally increased. The increase in light transmittance is very preferable because it increases the light absorption in the photoelectric conversion film 12 and increases the photoelectric conversion performance. In consideration of suppression of leakage current, increase in resistance value of thin film, and increase in transmittance accompanying thinning of the transparent conductive material film, the thickness of the transparent conductive material film is preferably 5 to 100 nm, More preferably, it is 5 to 20 nm.

  When the surface of the lower electrode 11 has irregularities, or when dust adheres to the surface of the lower electrode 11, a low molecular organic photoelectric conversion material is deposited thereon to form the photoelectric conversion film 12. The conversion film 12 is likely to have a fine crack or a portion where the photoelectric conversion film 12 is only formed thin. At this time, if the upper electrode 13 is further formed thereon, the crack is covered by the transparent conductive material film, and the photoelectric conversion film 12 and the upper electrode 13 are partially close to each other. Prone to occur. In particular, when TCO is used as the upper electrode 13, the tendency is remarkable. As one method for preventing such an increase in leakage current, it is preferable to form an undercoat film on the lower electrode 11 to relieve unevenness. As the undercoat film, a method of forming a polymer material such as polyaniline, polythiophene, polypyrrole, polycarbazole, PTPDES, or PTPDK by a spin coating method is highly effective. When the photoelectric conversion film 12 is to be formed in a vacuum by vapor deposition or the like in order to prevent impurities from being mixed and to make a more evenly uniform laminated film, an amorphous film is used as the undercoat layer. It is preferable.

In addition, as a combination of the lower electrode 11, the organic photoelectric conversion material, and the upper electrode 13 capable of setting the visible light transmittance of the photoelectric conversion portion A to 50% or more, as shown in Examples described later, the lower electrode 11 and the upper electrode 13 may be ITO, and the organic photoelectric conversion material may be tin phthalocyanine. In addition to this, the lower electrode 11 and the upper electrode 13 are each made of IZO, AZO, FTO, SnO ₂ , TiO ₂ , or ZnO ₂ , and the organic photoelectric conversion material is any one of the above-described dyes, whereby the photoelectric conversion unit A The visible light transmittance of 50% or more can be realized.

(Second Embodiment of Photoelectric Conversion Element)
FIG. 2 is a schematic cross-sectional view showing a schematic configuration of the photoelectric conversion element according to the second embodiment of the present invention.
The photoelectric conversion element shown in FIG. 2A is a semiconductor substrate K such as silicon, a visible light photoelectric conversion unit B stacked above the semiconductor substrate K, and a layer stacked above the visible light photoelectric conversion unit B in FIG. The photoelectric conversion part A shown is provided.

  The visible light photoelectric conversion unit B has substantially the same configuration as that of the photoelectric conversion unit A. As an organic photoelectric conversion material constituting the photoelectric conversion film 12 of the photoelectric conversion unit A, a range that combines the visible region and the infrared region (wavelength of 400 nm or more). The material having an absorption peak of the absorption spectrum in the visible range in the visible region and generating a charge according to the absorbed light is used.

  In the semiconductor substrate K, there is formed a storage unit 3 for storing charges generated in the photoelectric conversion film 12 of the photoelectric conversion unit A and transferred to the upper electrode 13, and the storage unit 3 and the upper electrode 13 are connected to each other. The parts 6 are electrically connected. Further, in the semiconductor substrate K, there is formed a storage portion 4 for storing charges generated in the photoelectric conversion film of the photoelectric conversion portion B and transferred to the upper electrode, and the storage portion 4 and the upper electrode are connected to each other. 7 is electrically connected.

  The photoelectric conversion element illustrated in FIG. 2B includes a semiconductor substrate K such as silicon and the photoelectric conversion unit A illustrated in FIG. 1 stacked above the semiconductor substrate K. In the semiconductor substrate K below the photoelectric conversion part A, the absorption peak of the absorption spectrum in the range including the visible region and the infrared region (wavelength of 400 nm or more) is in the visible region, and a charge corresponding to the absorbed light is generated. A visible light photoelectric conversion unit C is formed. In addition, in the semiconductor substrate K, a storage unit 3 ′ for storing charges generated in the photoelectric conversion film 12 of the photoelectric conversion unit A and transferred to the upper electrode 13 is formed. The storage unit 3 ′ and the upper electrode are formed. 13 is electrically connected by a connecting portion 6 '. The visible light photoelectric conversion unit C is configured by, for example, a known pn junction photodiode.

  2A and 2B, a signal corresponding to the infrared light is acquired by the electric charge generated in the photoelectric conversion unit A installed in the upper layer, and the signal is installed below the photoelectric conversion unit A. It is possible to realize a photoelectric conversion element that can acquire a signal corresponding to visible light by the electric charges generated in the photoelectric conversion unit B and the photoelectric conversion unit C.

  In the case of the configuration of FIG. 2A, for example, a signal corresponding to infrared light and a signal corresponding to G light are configured by configuring the photoelectric conversion film of the photoelectric conversion unit B with a quinacridone-based organic material (for example, quinacridone). Can be obtained at the same time. For this reason, a number of photoelectric conversion elements in FIG. 2A are two-dimensionally arranged on the same plane, and a signal readout circuit such as a CCD or CMOS circuit that reads out a signal corresponding to the charge generated in each photoelectric conversion element is used as a semiconductor. By providing the substrate K, it is possible to realize an infrared / visible imaging element capable of simultaneously capturing an infrared image corresponding to infrared light and a monochrome image corresponding to G light.

  In addition, a photoelectric conversion element in which the photoelectric conversion film of the photoelectric conversion unit B is a quinacridone-based organic material (for example, quinacridone), and a photoelectric conversion element in which the photoelectric conversion film of the photoelectric conversion unit B is a phthalocyanine-based organic material (for example, zinc phthalocyanine) CCD or CMOS which reads a signal corresponding to the electric charge generated in each photoelectric conversion element by arranging a large number of photoelectric conversion elements in which the photoelectric conversion film of the photoelectric conversion part B is a porphyrin organic compound two-dimensionally on the same plane By providing a signal readout circuit such as a circuit on the semiconductor substrate K, it is possible to simultaneously capture an infrared image corresponding to infrared light and a color image corresponding to R, G, B light by known signal processing. An infrared / visible imaging device can be realized.

  In FIG. 2A, two more photoelectric conversion units B are provided between the photoelectric conversion unit A and the photoelectric conversion unit B, or between the semiconductor substrate K and the photoelectric conversion unit B. By making the material of the photoelectric conversion film of the photoelectric conversion part B into quinacridone, zinc phthalocyanine, and a porphyrin-based organic compound, the photoelectric conversion part A generates signals corresponding to infrared light from the three photoelectric conversion parts B. A signal corresponding to the R, G, B light can be obtained. For this reason, a number of photoelectric conversion elements in FIG. 2A are two-dimensionally arranged on the same plane, and a signal readout circuit such as a CCD or CMOS circuit that reads out a signal corresponding to the charge generated in each photoelectric conversion element is used as a semiconductor. By providing the substrate K, it is possible to realize an infrared / visible imaging element capable of simultaneously capturing an infrared image corresponding to infrared light and a color image corresponding to R, G, B light. . Of course, a configuration in which one or more photoelectric conversion units B are provided between the photoelectric conversion unit A and the photoelectric conversion unit B or between the semiconductor substrate K and the photoelectric conversion unit B is also possible depending on the use application. It is.

  In the case of the configuration of FIG. 2B, the photoelectric conversion unit C itself is a pn junction photodiode and basically has sensitivity to light having a wavelength of 1100 nm or less, and therefore the infrared light absorbed by the photoelectric conversion unit A is absorbed. It has sensitivity for light other than light. When there is nothing other than the photoelectric conversion unit A that absorbs light, the light incident on the photoelectric conversion unit C is the entire light having a wavelength transmitted through the photoelectric conversion unit A, and a signal corresponding to infrared light and visible light. Can be obtained simultaneously. For this reason, a large number of photoelectric conversion elements in FIG. 2B are two-dimensionally arranged on the same plane, and a signal readout circuit such as a CCD or CMOS circuit that reads out a signal corresponding to the charge generated in each photoelectric conversion element is used as a semiconductor. By providing the substrate K, it is possible to realize an infrared / visible imaging element capable of simultaneously capturing an infrared image corresponding to infrared light and a monochrome image corresponding to visible light.

  For the photoelectric conversion part C, as described in US Pat. No. 5,965,875, pn junction surfaces are formed at a depth that absorbs R light, a depth that absorbs G light, and a depth that absorbs B light, respectively. By separating the wavelengths absorbed in the depth direction of silicon and forming three photoelectric conversion portions C in the depth direction so as to obtain signals corresponding to the respective absorption wavelengths, the photoelectric conversion portions A are transmitted. A color signal can be acquired from visible light, and a signal corresponding to infrared light and a signal corresponding to R, G, B light can be acquired simultaneously. Of course, a configuration in which two or four or more photoelectric conversion units C are stacked in the depth direction in the semiconductor substrate K below the photoelectric conversion unit A is also possible depending on the intended use.

  If a spectral filter that transmits light in a specific wavelength region is installed above the photoelectric conversion unit A, the light incident on the photoelectric conversion unit C can be dispersed. As the spectral filter, it is possible to use a primary color system or a complementary color system color filter used in a normal CCD or CMOS color image sensor. A color filter used in a CCD or CMOS color image sensor generally has a characteristic of transmitting a part of infrared light. Therefore, even when the color filter is arranged above the photoelectric conversion unit A, infrared light is transmitted to the photoelectric conversion unit A. Can be incident.

  For example, a photoelectric conversion element provided with an R color filter that transmits a part of R light and infrared light above the photoelectric conversion unit A in FIG. 2B, and a G conversion above the photoelectric conversion unit A in FIG. A photoelectric conversion element provided with a G color filter that transmits part of light and infrared light, and a B color filter that transmits part of B light and infrared light above the photoelectric conversion part A in FIG. A large number of the photoelectric conversion elements provided are arranged on the same plane, and a signal reading circuit such as a CCD or a CMOS circuit for reading a signal corresponding to the electric charge generated in each photoelectric conversion element is provided on the semiconductor substrate K. By the signal processing, an infrared / visible imaging element capable of capturing an infrared image and a color image can be realized.

  According to the photoelectric conversion elements shown in FIGS. 2 (a) and 2 (b), the photoelectric conversion units for detecting different lights are stacked in the vertical direction. Almost all can be taken out as a signal, and since there is no loss of light quantity, high sensitivity can be realized. Furthermore, in a normal Si photoelectric conversion device, an infrared cut filter is provided to cut a signal due to infrared light, but the uppermost photoelectric conversion unit A can play a part or all of the role. Therefore, when applied to an image sensor, an effect of eliminating part of the infrared cut filter is obtained.

2 (a) and 2 (b), one or more photoelectric conversion elements B or photoelectric conversion units C are stacked below the photoelectric conversion unit A, but as shown in FIG. 2 (c). In the semiconductor substrate K below the photoelectric conversion unit A, a plurality of photoelectric conversion units C are arranged in a direction perpendicular to the incident direction of light incident on the semiconductor substrate K (a direction parallel to the surface of the semiconductor substrate K). The structure which was made can also be considered. For example, three pn junction photodiodes are arranged in the vertical direction as the photoelectric conversion unit C in the semiconductor substrate K below the photoelectric conversion unit A, and an R color filter and a G color filter are disposed above each of the three pn junction photodiodes. , B color filter is arranged. Then, by arranging a large number of such photoelectric conversion elements on the same plane and providing a signal reading circuit such as a CCD or CMOS circuit on the semiconductor substrate K for reading a signal corresponding to the charge generated in each photoelectric conversion element, It is possible to realize an infrared / visible imaging element capable of simultaneously capturing an infrared image and a color image in which each photoelectric conversion element and pixel have a one-to-one correspondence.
The pixel sizes of the photoelectric conversion unit A and the photoelectric conversion units B and C can be assigned to different sizes.

  In FIG. 2C, a plurality of photoelectric conversion units C correspond to one photoelectric conversion unit A. However, the incident side is a plurality of conversion units and the substrate side is a single conversion unit. In addition, as shown in FIG. 2D, a configuration in which one photoelectric conversion unit C corresponds to two photoelectric conversion units A can be used depending on usage.

  In the configuration example illustrated in FIG. 2, the photoelectric conversion unit A and the photoelectric conversion unit B are configured such that light transmitted through the photoelectric conversion unit A enters the photoelectric conversion unit B. Needless to say, and are overlapped in plan view. Similarly, in the photoelectric conversion unit A and the photoelectric conversion unit C, the photoelectric conversion unit A and the photoelectric conversion unit C overlap in plan view so that light transmitted through the photoelectric conversion unit A enters the photoelectric conversion unit C. Needless to say.

  Next, a more preferable form of the photoelectric conversion unit A shown in FIG. 1 will be described. The photoelectric conversion unit A described below has a configuration as shown in FIG. In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals.

  In the photoelectric conversion part A, the voltage application method and the element material configuration were performed so as to collect the signal charges having a smaller hole and electron transportability in the organic film from the upper electrode 13 side on the light incident side. This is preferable because the photoelectric conversion efficiency is large and the spectral sensitivity becomes sharp. In the photoelectric conversion film 12 of the photoelectric conversion part A, light absorption mainly occurs on the light incident side. Therefore, by collecting charges having low transportability from the upper electrode 13 closer to the light incident side, the charge transport distance. Therefore, charge deactivation during transportation is reduced and efficiency is increased. If the charge is collected in the direction opposite to the above, the longer the absorption rate, the longer the transport distance because the charge generation part is closer to the upper electrode 13 side. At wavelengths where the absorption rate of light reaching the back of the film is low and the absorption rate is low, the charge generation site is at the back of the film, which shortens the transport distance and increases the collection efficiency. Spectral sensitivity becomes broad. In an organic film, there are many materials having a large hole transport ability. In this case, a voltage is applied so as to collect electrons from the upper electrode 13, and holes are collected from the lower electrode 11 to generate a signal. A format for storing, transferring and reading is desirable.

  Hereinafter, a case where electrons are collected from the upper electrode 13 will be described. When collecting holes from the upper electrode 13, it is only necessary to reverse the order of film formation except for the undercoat film 121 and the work function adjusting film 126. The work function adjusting film 126 may be changed so as to select a work function having a large work function.

  As shown in FIG. 3, an undercoat film 121 and an electron blocking film 122 are provided between the photoelectric conversion film 12 and the lower electrode 11 of the photoelectric conversion unit A, and between the photoelectric conversion film 12 and the upper electrode 13. Is preferably provided with a hole blocking film 124, a hole blocking / buffer film 125, and a work function adjusting film 126.

  The organic photoelectric conversion material constituting the photoelectric conversion film 12 preferably contains at least one of an organic p-type semiconductor and an organic n-type semiconductor.

  The organic p-type semiconductor (compound) is a donor-type organic semiconductor (compound), which is mainly represented by a hole-transporting organic compound and refers to an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Therefore, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound. For example, triarylamine compound, benzidine compound, pyrazoline compound, styrylamine compound, hydrazone compound, triphenylmethane compound, carbazole compound, polysilane compound, thiophene compound, phthalocyanine compound, cyanine compound, merocyanine compound, oxonol compound, polyamine compound, indole Compounds, pyrrole compounds, pyrazole compounds, polyarylene compounds, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), nitrogen-containing heterocyclic compounds The metal complex etc. which it has as can be used. Not limited to this, as described above, any organic compound having an ionization potential smaller than that of the organic compound used as the n-type (acceptor property) compound may be used as the donor organic semiconductor.

  Organic n-type semiconductors (compounds) are acceptor organic semiconductors (compounds), which are mainly represented by electron-transporting organic compounds and refer to organic compounds that easily accept electrons. More specifically, the organic compound having the higher electron affinity when two organic compounds are used in contact with each other. Therefore, as the acceptor organic compound, any organic compound can be used as long as it is an electron-accepting organic compound. For example, condensed aromatic carbocyclic compounds (naphthalene derivatives, anthracene derivatives, phenanthrene derivatives, tetracene derivatives, pyrene derivatives, perylene derivatives, fluoranthene derivatives), 5- to 7-membered heterocyclic compounds containing nitrogen atoms, oxygen atoms, and sulfur atoms (E.g. pyridine, pyrazine, pyrimidine, pyridazine, triazine, quinoline, quinoxaline, quinazoline, phthalazine, cinnoline, isoquinoline, pteridine, acridine, phenazine, phenanthroline, tetrazole, pyrazole, imidazole, thiazole, oxazole, indazole, benzimidazole, benzotriazole, Benzoxazole, benzothiazole, carbazole, purine, triazolopyridazine, triazolopyrimidine, tetrazaindene, o Metal complexes having ligands such as saziazole, imidazopyridine, pyralidine, pyrrolopyridine, thiadiazolopyridine, dibenzazepine, tribenzazepine), polyarylene compounds, fluorene compounds, cyclopentadiene compounds, silyl compounds, and nitrogen-containing heterocyclic compounds. Etc. Note that the present invention is not limited thereto, and as described above, any organic compound having an electron affinity higher than that of the organic compound used as the donor organic compound may be used as the acceptor organic semiconductor.

  Next, the metal complex compound will be described. The metal complex compound is a metal complex having a ligand having at least one nitrogen atom or oxygen atom or sulfur atom coordinated to the metal, and the metal ion in the metal complex is not particularly limited, but preferably beryllium ion, magnesium Ion, aluminum ion, gallium ion, zinc ion, indium ion, or tin ion, more preferably beryllium ion, aluminum ion, gallium ion, or zinc ion, and still more preferably aluminum ion or zinc ion. As the ligand contained in the metal complex, there are various known ligands. For example, “Photochemistry and Photophysics of Coordination Compounds” published by Springer-Verlag H. Yersin in 1987, “Organometallic Chemistry— Examples of the ligands described in “Basics and Applications—” published by Akio Yamamoto, 1982, etc.

  The ligand is preferably a nitrogen-containing heterocyclic ligand (preferably having 1 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 3 to 15 carbon atoms, and a monodentate ligand. Or a bidentate or higher ligand, preferably a bidentate ligand such as a pyridine ligand, a bipyridyl ligand, a quinolinol ligand, a hydroxyphenylazole ligand (hydroxyphenyl) Benzimidazole, hydroxyphenylbenzoxazole ligand, hydroxyphenylimidazole ligand)), alkoxy ligand (preferably 1-30 carbon atoms, more preferably 1-20 carbon atoms, particularly preferably carbon 1-10, for example, methoxy, ethoxy, butoxy, 2-ethylhexyloxy, etc.), aryloxy ligands Preferably it has 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenyloxy, 1-naphthyloxy, 2-naphthyloxy, 2,4,6-trimethylphenyl Oxy, 4-biphenyloxy, etc.), heteroaryloxy ligands (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as pyridyl. Oxy, pyrazyloxy, pyrimidyloxy, quinolyloxy, etc.), alkylthio ligands (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, Ethylthio, etc.), arylthio ligands (preferably having 6 to 30 carbon atoms, more preferred) Has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, etc.), a heterocyclic substituted thio ligand (preferably 1 to 30 carbon atoms, more preferably 1 to carbon atoms). 20, particularly preferably 1 to 12 carbon atoms, such as pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like, or siloxy ligand (preferably Has 1 to 30 carbon atoms, more preferably 3 to 25 carbon atoms, particularly preferably 6 to 20 carbon atoms, and examples thereof include a triphenylsiloxy group, a triethoxysiloxy group, and a triisopropylsiloxy group. More preferably a nitrogen-containing heterocyclic ligand, an aryloxy ligand, a heteroaryloxy group, or a siloxy ligand, Preferably, a nitrogen-containing heterocyclic ligand, an aryloxy ligand, or a siloxy ligand is used.

  The photoelectric conversion film 12 includes a p-type semiconductor layer and an n-type semiconductor layer, at least one of the p-type semiconductor and the n-type semiconductor is an organic semiconductor, and the p-type semiconductor layer is interposed between the semiconductor layers. It is preferable to have a bulk heterojunction structure layer including an n-type semiconductor and an n-type semiconductor as an intermediate layer. In such a case, by including a bulk heterojunction structure in the photoelectric conversion film 12, it is possible to compensate for the shortcoming of the short carrier diffusion length of the photoelectric conversion film 12 and to improve the photoelectric conversion efficiency. The bulk heterojunction structure is described in detail in JP-A-2005-303266.

  Further, the photoelectric conversion film 12 preferably has a structure having two or more repeating structures (tandem structures) of a pn junction layer formed of a p-type semiconductor layer and an n-type semiconductor layer, and more preferably, In this case, a thin layer of conductive material is inserted between the repeated structures. The number of repeating structures (tandem structures) of the pn junction layer may be any number, but is preferably 2 to 50, more preferably 2 to 30, particularly preferably 2 or 10 in order to increase the photoelectric conversion efficiency. It is. Silver or gold is preferable as the conductive material, and silver is most preferable. The tandem structure is described in detail in Japanese Patent Application Laid-Open No. 2006-086493.

  The photoelectric conversion film 12 has a p-type semiconductor layer, an n-type semiconductor layer (preferably a mixed / dispersed (bulk heterojunction structure) layer), and is formed on at least one of the p-type semiconductor and the n-type semiconductor. The case where an organic compound whose orientation is controlled is preferable, and the case where an organic compound whose orientation is controlled (possible) is included in both the p-type semiconductor and the n-type semiconductor is more preferable. As this organic compound, those having π-conjugated electrons are preferably used, and it is more preferable that the π-electron plane is oriented at an angle close to parallel rather than perpendicular to the substrate (electrode substrate). The angle with respect to the substrate is preferably 0 ° or more and 80 ° or less, more preferably 0 ° or more and 60 ° or less, further preferably 0 ° or more and 40 ° or less, and further preferably 0 ° or more and 20 ° or less. Particularly preferably, it is 0 ° or more and 10 ° or less, and most preferably 0 ° (that is, parallel to the substrate). As described above, the organic compound layer whose orientation is controlled may be partially included in the entire photoelectric conversion film 12, but preferably, the ratio of the portion whose orientation is controlled with respect to the entire photoelectric conversion film 12 is 10% or more, more preferably 30% or more, more preferably 50% or more, further preferably 70% or more, particularly preferably 90% or more, and most preferably 100%. Such a state compensates for the short carrier diffusion length of the photoelectric conversion film 12 by controlling the orientation of the organic compound contained in the photoelectric conversion film 12, and improves the photoelectric conversion efficiency.

  In the case where the orientation of the organic compound is controlled, it is more preferable that the heterojunction plane (for example, the pn junction plane) is not parallel to the substrate. It is more preferable that the heterojunction plane is oriented not at a parallel to the substrate (electrode substrate) but at an angle close to the vertical. The angle with respect to the substrate is preferably 10 ° or more and 90 ° or less, more preferably 30 ° or more and 90 ° or less, further preferably 50 ° or more and 90 ° or less, and further preferably 70 ° or more and 90 ° or less. Particularly preferably, it is 80 ° or more and 90 ° or less, and most preferably 90 ° (that is, perpendicular to the substrate). The organic compound layer whose heterojunction surface is controlled as described above may be partially included in the entire photoelectric conversion film 12. Preferably, the ratio of the portion whose orientation is controlled with respect to the entire photoelectric conversion film 12 is 10% or more, more preferably 30% or more, more preferably 50% or more, still more preferably 70% or more, and particularly preferably. 90% or more, most preferably 100%. In such a case, the area of the heterojunction surface in the photoelectric conversion film 12 is increased, the amount of carriers such as electrons, holes, and electron-hole pairs generated at the interface is increased, and the photoelectric conversion efficiency can be improved. In the above-described photoelectric conversion film in which the orientation of both the heterojunction plane and the π-electron plane of the organic compound is controlled, the photoelectric conversion efficiency can be particularly improved. These states are described in detail in Japanese Patent Application Laid-Open No. 2006-086493. In terms of light absorption, the thickness of the organic dye layer is preferably as large as possible, but considering the ratio that does not contribute to charge separation, the thickness of the organic dye layer is preferably 30 nm to 300 nm, more preferably 50 nm to 250 nm, Especially preferably, it is 80 nm or more and 200 nm or less.

In the case where a polymer compound is used as at least one of the p-type semiconductor (compound) and the n-type semiconductor (compound), it is preferable to form the film by a wet film forming method that is easy to prepare. When a dry film formation method such as vapor deposition is used, it is difficult to use a polymer because it may be decomposed, and an oligomer thereof can be preferably used instead. On the other hand, when a low molecule is used, a dry film forming method is preferably used, and a vacuum deposition method is particularly preferably used. The vacuum deposition method is basically based on the method of heating compounds such as resistance heating deposition method and electron beam heating deposition method, shape of deposition source such as crucible and boat, degree of vacuum, deposition temperature, base temperature, deposition rate, etc. It is a parameter. In order to make uniform deposition possible, it is preferable to perform deposition by rotating the substrate. The degree of vacuum is preferably higher, and vacuum deposition is performed at 10 ⁻⁴ Torr or less, preferably 10 ⁻⁶ Torr or less, particularly preferably 10 ⁻⁸ Torr or less. It is preferable that all steps during the vapor deposition are performed in a vacuum, and basically the compound is not directly in contact with oxygen and moisture in the outside air. The above-described conditions for vacuum deposition need to be strictly controlled because they affect the crystallinity, amorphousness, density, density, etc. of the organic film. It is preferable to use PI or PID control of the deposition rate using a film thickness monitor such as a quartz crystal resonator or an interferometer. When two or more kinds of compounds are vapor-deposited simultaneously, a co-evaporation method, a flash vapor deposition method, or the like can be preferably used.

  As described above, the undercoat film 121 is for suppressing a DC short circuit and an increase in leakage current due to the unevenness of the surface of the lower electrode 11.

  The electron blocking film 122 is provided in order to reduce dark current due to injection of electrons from the lower electrode 11, and blocks injection of electrons from the lower electrode 11 into the photoelectric conversion film 12. The electron blocking film 122 can also be used as the undercoat film 121.

  The hole blocking film 124 is provided in order to reduce dark current due to injection of holes from the upper electrode 13, and prevents holes from the upper electrode 13 from being injected into the photoelectric conversion film 12. To do. The electron blocking film 122 and the hole blocking film 124 are collectively referred to as a charge blocking layer. In the photoelectric conversion element of this embodiment, a charge blocking layer that prevents injection of charges from the electrodes 11 and 13 is provided in at least one of the upper layer and the lower layer of the photoelectric conversion film 12.

  The hole blocking / buffer film 125 has the function of the hole blocking film 124 and the function of reducing damage to the photoelectric conversion film 12 when the upper electrode 13 is formed. When the upper electrode 13 is formed on the photoelectric conversion film 12, high energy particles existing in the apparatus used for forming the upper electrode 13, for example, sputtering, sputter particles, secondary electrons, Ar particles, oxygen When negative ions or the like collide with the photoelectric conversion film 12, the photoelectric conversion film 12 may be altered and performance degradation may occur, such as an increase in leakage current or a decrease in sensitivity. As one method for preventing this, it is preferable to provide the buffer film 125 on the photoelectric conversion film 12.

  The material of the hole blocking / buffer film 125 is preferably an organic substance such as copper phthalocyanine, PTCDA, acetylacetonate complex, or BCP, an organic-metal compound, or an inorganic substance such as MgAg or MgO. Further, the hole blocking and buffer film 125 preferably has a high visible light transmittance so as not to prevent light absorption of the photoelectric conversion film 12, and a material that does not absorb in the visible region is selected. It is preferable to use an extremely thin film thickness. The film thickness of the hole blocking / buffer film 125 varies depending on the structure of the photoelectric conversion film 12, the film thickness of the upper electrode 13, and the like, but it is particularly preferable to use a film thickness of 2 to 50 nm.

The work function adjustment film 126 is for adjusting the work function of the upper electrode 13 and suppressing dark current. When the upper electrode 13 is made of a material having a relatively large work function (for example, 4.5 eV or more) (for example, any one of ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , and FTO), the work function is adjusted. As a material of the film 126, a dark current can be effectively suppressed by using a material containing a metal having a work function of 4.5 eV or less (for example, In). The description of the advantages and the like by providing such a work function adjusting film 126 will be described later.

  The lower electrode 11 is selected in consideration of adhesion to an adjacent film, electron affinity, ionization potential, stability, and the like in order to take out holes from the photoelectric conversion film 12 and collect them. Since the upper electrode 13 takes out electrons from the photoelectric conversion film 12 and discharges the electrons, the upper electrode 13 is selected in consideration of adhesion to an adjacent film, electron affinity, ionization potential, stability, and the like.

  Various methods are used for producing the electrode depending on the material. For example, in the case of ITO, an electron beam method, a sputtering method, a resistance heating vapor deposition method, a chemical reaction method (sol-gel method, etc.), a coating of a dispersion of indium tin oxide, etc. A film is formed by this method. In the case of ITO, UV-ozone treatment, plasma treatment, etc. can be performed.

  The conditions for forming a transparent electrode film (transparent electrode film) will be described. The silicon substrate temperature at the time of forming the transparent electrode film is preferably 500 ° C. or lower, more preferably 300 ° C. or lower, further preferably 200 ° C. or lower, and further preferably 150 ° C. or lower. Further, a gas may be introduced during the formation of the transparent electrode film, and basically the gas species is not limited, but Ar, He, oxygen, nitrogen and the like can be used. Further, a mixed gas of these gases may be used. In particular, in the case of an oxide material, oxygen defects are often introduced, so that oxygen is preferably used.

  Further, the preferred range of the surface resistance of the transparent electrode film varies depending on whether it is the lower electrode 11 or the upper electrode 13. When the signal readout portion has a CMOS structure, the surface resistance of the transparent conductive film is preferably 10000Ω / □ (ohms per square) or less, more preferably 1000Ω / □ or less. If the signal reading unit has a CCD structure, the surface resistance is preferably 1000Ω / □ or less, and more preferably 100Ω / □ or less. When used for the upper electrode 13, it is preferably 1000000 Ω / □ or less, more preferably 100000 Ω / □ or less.

  The upper electrode 13 is preferably made plasma-free. By creating the upper electrode 13 in a plasma-free manner, the influence of plasma on the substrate can be reduced, and the photoelectric conversion characteristics can be improved. Here, plasma free means that no plasma is generated during the deposition of the upper electrode 13 or that the distance from the plasma generation source to the substrate is 2 cm or more, preferably 10 cm or more, more preferably 20 cm or more. It means a state in which the plasma that reaches is reduced.

  Examples of an apparatus that does not generate plasma during the formation of the upper electrode 13 include an electron beam vapor deposition apparatus (EB vapor deposition apparatus) and a pulse laser vapor deposition apparatus. Regarding EB deposition equipment or pulse laser deposition equipment, “Surveillance of Transparent Conductive Films” supervised by Yutaka Sawada (published by CMC, 1999); ), "Transparent conductive film technology" by the Japan Society for the Promotion of Science (Ohm Co., 1999), and the references attached thereto, etc. can be used. Hereinafter, a method of forming a transparent electrode film using an EB vapor deposition apparatus is referred to as an EB vapor deposition method, and a method of forming a transparent electrode film using a pulse laser vapor deposition apparatus is referred to as a pulse laser vapor deposition method.

  For an apparatus that can realize a state in which the distance from the plasma generation source to the substrate is 2 cm or more and the arrival of plasma to the substrate is reduced (hereinafter referred to as a plasma-free film forming apparatus), for example, an opposed target sputtering Equipment, arc plasma deposition, etc. are considered, and these are supervised by Yutaka Sawada "New development of transparent conductive film" (published by CMC, 1999), and supervised by Yutaka Sawada "New development of transparent conductive film II" (published by CMC) 2002), “Transparent conductive film technology” (Ohm Co., 1999) by the Japan Society for the Promotion of Science, and references and the like attached thereto can be used.

  The material of the transparent electrode film is preferably one that can be formed by a plasma-free film forming apparatus, an EB vapor deposition apparatus, and a pulse laser vapor deposition apparatus. For example, a metal, an alloy, a metal oxide, a metal nitride, a metal boride, an organic conductive compound, a mixture thereof, and the like are preferable. Specific examples include tin oxide, zinc oxide, indium oxide, and indium zinc oxide. (IZO), indium tin oxide (ITO), conductive metal oxides such as indium tungsten oxide (IWO), metal nitrides such as titanium nitride, metals such as gold, platinum, silver, chromium, nickel, aluminum, and these A mixture or laminate of a metal and a conductive metal oxide, an inorganic conductive material such as copper iodide or copper sulfide, an organic conductive material such as polyaniline, polythiophene or polypyrrole, a laminate of these and ITO, Etc. Also, supervised by Yutaka Sawada “New Development of Transparent Conductive Film” (published by CMC, 1999), supervised by Yutaka Sawada “New Development of Transparent Conductive Film II” (published by CMC, 2002), “Transparency by Japan Society for the Promotion of Science” Those described in detail in “Technology of Conductive Film” (Ohm Co., 1999) may be used.

Next, advantages of providing the work function adjusting film 126 will be described.
When the upper electrode 13 is made of a material having high work function such as ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , and FTO and having high transparency, the dark current when the bias is applied to the upper electrode 13 is 1 V At the time of application, it becomes considerably large as about 10 μA / cm ² . As one of the causes of the dark current, a current flowing from the upper electrode 13 to the photoelectric conversion film 12 when a bias is applied can be considered. When a highly transparent electrode such as ITO, IZO, ZnO ₂ , SnO ₂ , TiO ₂ , and FTO is used as the upper electrode 13, the work function is relatively large (4.5 eV or more), so It was thought that the barrier when moving to the photoelectric conversion film 12 was lowered, and hole injection into the photoelectric conversion film 12 was likely to occur. Actually, when examining the work function of highly transparent metal oxide based transparent electrodes such as ITO, IZO, SnO ₂ , TiO ₂ , and FTO, for example, the work function of the ITO electrode is about 4.8 eV. The work function of the (aluminum) electrode is considerably higher than that of about 4.3 eV, and other metal oxide-based transparent electrodes other than ITO also have the smallest AZO (Al-doped zinc oxide). Except for about 4.5 eV, it is known that its work function is relatively large, about 4.6 to 5.4 (for example, J. Vac. Sci. Technol. A17 (4), Jul. / See Fig. 12 of Aug 1999 p. 1765-1772).

  When the work function of the upper electrode 13 is relatively large (4.8 eV), the barrier when holes move to the photoelectric conversion film 12 when a bias is applied is lowered, and holes from the upper electrode 13 to the photoelectric conversion film 12 are reduced. Implantation is likely to occur, and as a result, the dark current is considered to increase. In this embodiment, since the hole blocking film 124 is provided, dark current is suppressed. However, if the work function of the upper electrode 13 is large, it is difficult to suppress dark current even if the hole blocking film 124 is present. .

  Therefore, in this embodiment, a film having a work function of 4.5 eV or less is provided between the upper electrode 13 and the photoelectric conversion film 12.

  In the following, metals having a work function of 4.5 eV or less are listed together with their characteristics.

(Third Embodiment of Photoelectric Conversion Element)
In the present embodiment, a configuration in which an imaging element is realized using the photoelectric conversion element having the configuration illustrated in FIG.
FIG. 4 is a partial surface schematic diagram of an image sensor for explaining an embodiment of the present invention. FIG. 5 is a schematic sectional view taken along line XX of the image sensor shown in FIG. In FIG. 4, the microlens 14 is not shown. In FIG. 5, the same reference numerals are given to the same components as those in FIG.

  A p-well layer 2 is formed on the n-type silicon substrate 1. Hereinafter, the n-type silicon substrate 1 and the p-well layer 2 are collectively referred to as a semiconductor substrate. A color filter 13r that mainly transmits R light, a color filter 13g that mainly transmits G light, and a color filter that mainly transmits B light in a row direction on the same plane above the semiconductor substrate and in a column direction perpendicular thereto. A number of three types of color filters 13b are arranged.

  A known material can be used for the color filter 13r, but such a material transmits part of infrared light in addition to R light. A known material can be used for the color filter 13g, but such a material transmits part of infrared light in addition to G light. A known material can be used for the color filter 13b, but such a material transmits part of infrared light in addition to B light.

  As the arrangement of the color filters 13r, 13g, 13b, a color filter arrangement (Bayer arrangement, vertical stripe, horizontal stripe, etc.) used in a known single-plate solid-state imaging device can be adopted.

  In the p well layer 2 below the color filter 13r, an n-type impurity region (hereinafter referred to as n region) 3r is formed corresponding to the color filter 13r, and a pn junction between the n region 3r and the p well layer 2 is formed. Thus, an R photoelectric conversion element (corresponding to the photoelectric conversion unit C in FIG. 2B) corresponding to the color filter 13r is configured.

  An n region 3g is formed in the p well layer 2 below the color filter 13g so as to correspond to the color filter 13g, and the G region corresponding to the color filter 13g is formed by a pn junction between the n region 3g and the p well layer 2. A photoelectric conversion element (corresponding to the photoelectric conversion unit C in FIG. 2B) is configured.

  An n region 3b is formed in the p well layer 2 below the color filter 13b so as to correspond to the color filter 13b, and B corresponding to the color filter 13b is formed by a pn junction between the n region 3b and the p well layer 2. A photoelectric conversion element (corresponding to the photoelectric conversion unit C in FIG. 2B) is configured.

  A transparent electrode 11r is formed above the n region 3r, a transparent electrode 11g is formed above the n region 3g, and a transparent electrode 11b is formed above the n region 3b. The transparent electrodes 11r, 11g, and 11b are divided corresponding to the color filters 13r, 13g, and 13b, respectively. The transparent electrodes 11r, 11g, and 11b have the same functions as the lower electrode 11 in FIG.

  On each of the transparent electrodes 11r, 11g, and 11b, a photoelectric conversion film 12 having a single configuration common to each of the color filters 13r, 13g, and 13b is formed.

  On the photoelectric conversion film 12, an upper electrode 13 having a single configuration common to each of the color filters 13r, 13g, and 13b is formed.

  A photoelectric conversion element corresponding to the color filter 13r (corresponding to the photoelectric conversion portion A in FIG. 2B) is formed by the transparent electrode 11r, the upper electrode 13 opposed to the transparent electrode 11r, and a part of the photoelectric conversion film 12 sandwiched therebetween. Is formed. Hereinafter, since this photoelectric conversion element is formed on a semiconductor substrate, it is referred to as an R-substrate photoelectric conversion element.

  A photoelectric conversion element corresponding to the color filter 13g (corresponding to the photoelectric conversion part A in FIG. 2B) is formed by the transparent electrode 11g, the upper electrode 13 opposed to the transparent electrode 11g, and a part of the photoelectric conversion film 12 sandwiched therebetween. Is formed. Hereinafter, this photoelectric conversion element is referred to as a G-substrate photoelectric conversion element.

  A photoelectric conversion element corresponding to the color filter 13b (corresponding to the photoelectric conversion portion A in FIG. 2B) is formed by the transparent electrode 11b, the upper electrode 13 facing the transparent electrode 11b, and a part of the photoelectric conversion film 12 sandwiched therebetween. Is formed. Hereinafter, this photoelectric conversion element is referred to as a B-substrate photoelectric conversion element.

  Next to the n region 3r in the p-well layer 2 is a high-concentration n-type impurity region (hereinafter referred to as an n + region) 4r for accumulating charges generated in the photoelectric conversion film 12 of the photoelectric conversion element on the R substrate. Is formed. In order to prevent light from entering the n + region 4r, it is preferable to provide a light shielding film on the n + region 4r.

  Next to the n region 3g in the p-well layer 2, an n + region 4g for accumulating charges generated in the photoelectric conversion film 12 of the photoelectric conversion element on the G substrate is formed. In order to prevent light from entering the n + region 4g, it is preferable to provide a light shielding film on the n + region 4g.

  Next to the n region 3b in the p well layer 2, an n + region 4b for accumulating charges generated in the photoelectric conversion film 12 of the photoelectric conversion element on the B substrate is formed. In order to prevent light from entering the n + region 4b, it is preferable to provide a light shielding film on the n + region 4b.

  A contact portion 6r made of a metal such as aluminum is formed on the n + region 4r, and a transparent electrode 11r is formed on the contact portion 6r. The n + region 4r and the transparent electrode 11r are electrically connected by the contact portion 6r. ing. The contact portion 6r is embedded in the insulating layer 5 that is transparent to visible light and infrared light.

  A contact portion 6g made of a metal such as aluminum is formed on the n + region 4g, and a transparent electrode 11g is formed on the contact portion 6g. The n + region 4g and the transparent electrode 11g are electrically connected by the contact portion 6g. ing. The contact portion 6g is embedded in the insulating layer 5.

  A contact portion 6b made of a metal such as aluminum is formed on the n + region 4b, and a transparent electrode 11b is formed on the contact portion 6b. The n + region 4b and the transparent electrode 11b are electrically connected by the contact portion 6b. ing. The contact portion 6 b is embedded in the insulating layer 5.

  In regions other than where the n regions 3r, 3g, 3b and n + regions 4r, 4g, 4b are formed in the p-well layer 2, depending on the charges generated in the R photoelectric conversion element and accumulated in the n region 3r. A signal reading unit 5r for reading out the corresponding signal and a signal corresponding to the charge accumulated in the n + region 4r, and a signal corresponding to the charge generated in the G photoelectric conversion element and accumulated in the n region 3g and the n + region 4g. A signal reading unit 5g for reading a signal corresponding to the charge accumulated in the signal, a signal corresponding to the charge generated in the B photoelectric conversion element and accumulated in the n region 3b, and a charge accumulated in the n + region 4b. A signal reading unit 5b for reading the corresponding signals is formed. Each of the signal reading units 5r, 5g, and 5b can adopt a known configuration using a CCD or a MOS circuit. In order to prevent light from entering the signal readout units 5r, 5g, 5b, it is preferable to provide a light shielding film on the signal readout units 5r, 5g, 5b.

  FIG. 6 is a diagram illustrating a specific configuration example of the signal reading unit 5r illustrated in FIG. In FIG. 6, the same components as those in FIGS. Note that the signal readout units 5r, 5g, and 5b have the same configuration, and thus the description of the signal readout units 5g and 5b is omitted.

  The signal readout section 5r has a reset transistor 43 whose drain is connected to the n + region 4r, its source connected to the power supply Vn, and an output transistor 42 whose gate is connected to the drain of the reset transistor 43 and whose source is connected to the power supply Vcc. A row selection transistor 41 whose source is connected to the drain of the output transistor 42 and whose drain is connected to the signal output line 45; a reset transistor 46 whose drain is connected to the n region 3r and whose source is connected to the power supply Vn; The output transistor 47 whose gate is connected to the drain of the reset transistor 46, the source is connected to the power supply Vcc, and the row selection transistor 48 whose source is connected to the drain of the output transistor 47 and whose drain is connected to the signal output line 49. With.

  By applying a bias voltage between the transparent electrode 11r and the upper electrode 13, a charge is generated according to the light incident on the photoelectric conversion film 12, and the charge moves to the n + region 4r through the transparent electrode 11r. The charge accumulated in the n + region 4r is converted into a signal corresponding to the amount of charge by the output transistor. Then, a signal is output to the signal output line 45 by turning on the row selection transistor 41. After the signal is output, the charge in the n + region 4r is reset by the reset transistor 43.

  The charge generated in the R photoelectric conversion element and accumulated in the n region 3r is converted into a signal corresponding to the charge amount by the output transistor 47. Then, a signal is output to the signal output line 49 by turning on the row selection transistor 48. After the signal is output, the charge in the n region 3r is reset by the reset transistor 46.

  Thus, the signal reading unit 5r can be configured by a known MOS circuit including three transistors.

  Returning to FIG. 5, two-layer protective layers 15 and 16 for protecting the photoelectric conversion element on the substrate are formed on the photoelectric conversion film 12, and color filters 13 r, 13 g, and 13 b are formed on the protective layer 16. On each of the color filters 13r, 13g, 13b, a microlens 14 for condensing light is formed on the corresponding n regions 3r, 3g, 3b.

  The image pickup device 100 is manufactured by forming the color filters 13r, 13g, 13b, the microlens 14 and the like after forming the photoelectric conversion film 12, but the color filters 13r, 13g, 13b and the microlens 14 are formed by photo When an organic material is used as the photoelectric conversion film 12 because it includes a lithography process and a baking process, the characteristics of the photoelectric conversion film 12 are deteriorated when the photolithography process and the baking process are performed with the photoelectric conversion film 12 exposed. Resulting in. In the imaging device 100, protective layers 15 and 16 are provided in order to prevent the deterioration of the characteristics of the photoelectric conversion film 12 due to such a manufacturing process.

The protective layer 15 is preferably an inorganic layer made of an inorganic material formed by the ALCVD method. The ALCVD method is an atomic layer CVD method, can form a dense inorganic layer, and can be an effective protective layer for the photoelectric conversion layer 12. The ALCVD method is also known as the ALE method or ALD method. The inorganic layer formed by the ALCVD method is preferably made of Al ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO ₂ , MgO, HfO ₂ , Ta ₂ O ₅ , more preferably made of Al ₂ O ₃ , SiO ₂ , Most preferably, it consists of Al ₂ O ₃ .

  The protective layer 16 is formed on the protective layer 15 in order to further improve the protective performance of the photoelectric conversion film 12, and is preferably an organic layer made of an organic polymer. Parylene is preferable as the organic polymer, and parylene C is more preferable. The protective layer 16 may be omitted, and the arrangement of the protective layer 15 and the protective layer 16 may be reversed. The protection effect of the photoelectric conversion film 12 is particularly high in the configuration shown in FIG.

  In the imaging device 100 having the above-described configuration, infrared light in the light transmitted through the color filter 13r out of incident light is absorbed by the photoelectric conversion film 12, and charges corresponding to the infrared light are generated here. To do. Similarly, infrared light out of the light transmitted through the color filter 13g out of the incident light is absorbed by the photoelectric conversion film 12, and charges corresponding to the infrared light are generated here. Similarly, infrared light out of the light transmitted through the color filter 13b out of the incident light is absorbed by the photoelectric conversion film 12, and charges corresponding to the infrared light are generated here.

  When a predetermined bias voltage is applied to the transparent electrode 11r and the upper electrode 13, charges generated in the photoelectric conversion film 12 constituting the photoelectric conversion element on the R substrate move to the n + region 4r via the transparent electrode 11r and the contact portion 6r. , Accumulated here. Then, a signal corresponding to the electric charge accumulated in the n + region 4r is read by the signal reading unit 5r and output to the outside of the image sensor 100.

  Similarly, when a predetermined bias voltage is applied to the transparent electrode 11g and the upper electrode 13, charges generated in the photoelectric conversion film 12 constituting the photoelectric conversion element on the G substrate are transferred to the n + region 4g via the transparent electrode 11g and the contact portion 6g. Go to and accumulate here. Then, a signal corresponding to the electric charge accumulated in the n + region 4g is read out by the signal reading unit 5g and output to the outside of the image sensor 100.

  Similarly, when a predetermined bias voltage is applied to the transparent electrode 11b and the upper electrode 13, charges generated in the photoelectric conversion film 12 constituting the photoelectric conversion element on the B substrate are transferred to the n + region 4b via the transparent electrode 11b and the contact portion 6b. Go to and accumulate here. Then, a signal corresponding to the electric charge accumulated in the n + region 4b is read by the signal reading unit 5b and output to the outside of the image sensor 100.

  The R light transmitted through the color filter 13r and transmitted through the photoelectric conversion film 12 enters the R photoelectric conversion element, and charges corresponding to the amount of incident light are accumulated in the n region 3r. Similarly, the G light transmitted through the color filter 13g and transmitted through the photoelectric conversion film 12 enters the G photoelectric conversion element, and charges corresponding to the amount of incident light are accumulated in the n region 3g. Similarly, the B light transmitted through the color filter 13b and transmitted through the photoelectric conversion film 12 enters the B photoelectric conversion element, and charges corresponding to the amount of incident light are accumulated in the n region 3b. The charges accumulated in the n regions 3r, 3g, and 3b are read by the signal reading units 5r, 5g, and 5b, and are output to the outside of the image sensor 100.

  The arrangement of signals read out and output from the n regions 3r, 3g, 3b is the same as the arrangement of signals output from the single-plate color solid-state image pickup device having the color filter arrangement as shown in FIG. By performing signal processing used in the color solid-state imaging device, color image data in which data of three color components of R, G, and B is given to one pixel data can be generated. Further, infrared image data in which one pixel data has infrared color component data can be generated by signals read out and output from the n + regions 4r, 4g, and 4b.

  As described above, the image sensor 100 generates the R component signal corresponding to the charge generated in the R photoelectric conversion element, the G component signal corresponding to the charge generated in the G photoelectric conversion element, and the B photoelectric conversion element. A B component signal corresponding to the charge, an IR component signal corresponding to the charge generated in the photoelectric conversion element on the R substrate, an IR component signal corresponding to the charge generated in the photoelectric conversion element on the G substrate, and the B substrate An IR component signal corresponding to the electric charge generated in the upper photoelectric conversion element can be output to the outside. For this reason, if the image sensor 100 is used, two types of image data, that is, color image data and infrared image data, can be obtained by one imaging. Therefore, this image sensor 100 can be used as, for example, an image sensor of an endoscope apparatus that requires an appearance image of a part to be inspected of a human body and an internal image of the part.

As a structure corresponding to the form of FIG. 3, amorphous ITO 30 nm is formed by sputtering to form the pixel electrode 11, on which compound 27 is 100 nm, compound 21 is 50 nm, compound 28 is 20 nm, and SiO film is 40 nm. A photoelectric conversion element was prepared by forming a film by vacuum heating vapor deposition in this order to form a photoelectric conversion layer 12 and further forming an amorphous ITO film of 5 nm by sputtering as an upper electrode to form a transparent electrode 13. All the vacuum evaporation of the photoelectric converting layer 12 was performed by the vacuum degree of 4 * 10 <^-4> Pa or less.

  In the same manner as in Example 1, except that the deposition of the compound 21 and the compound 1 was changed so as to be formed by a co-evaporation method in an amount of 50 nm in terms of a single film (in a ratio of 1: 1), respectively. A conversion element was created.

Comparative example

  In Example 1, the photoelectric conversion layer 12 was similarly changed except that the compound 27 was formed by vacuum heating vapor deposition in the order of 100 nm for the compound 27, 50 nm for the compound 21 and 40 nm for the SiO film. Produced.

The device performance was measured by measuring the photoelectric conversion efficiency at the absorption peak wavelength in the infrared region of Compound 21 at a dark current of 3 nA / cm ² . In addition, FIG. 7 shows the relative value (vertical axis in the figure) of the absorbance with respect to the light wavelength (nm) of compound 21.

  As a result of the measurement, assuming that the photoelectric conversion efficiency of the photoelectric conversion element of Comparative Example 1 is 100, the photoelectric conversion efficiency of the photoelectric conversion element of Example 1 is 800, and the photoelectric conversion efficiency of the photoelectric conversion element of Example 2 is 900. there were. For this reason, it was found that Examples 1 and 2 can improve the sensitivity while keeping the dark current low.

It is a cross-sectional schematic diagram which shows schematic structure of the photoelectric conversion element which is 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows schematic structure of the photoelectric conversion element which is 2nd Embodiment of this invention. It is a cross-sectional schematic diagram which shows another form of the photoelectric conversion element part shown in FIG. It is a partial surface schematic diagram of the image sensor of the present invention. It is a cross-sectional schematic diagram of the AA line of the image pick-up element shown in FIG. FIG. 6 is a diagram illustrating a specific configuration example of a signal reading unit illustrated in FIG. 5. It is a figure which shows the absorption peak with respect to the light wavelength of the compound 1 used in an Example.

Explanation of symbols

11 Lower electrode 12 Photoelectric conversion film 13 Upper electrode A Photoelectric conversion part

Claims (21)

A photoelectric conversion material that generates a charge according to incident light,
The photoelectric conversion material in which the said photoelectric conversion material contains the squarylium compound shown by following General formula (1) , and the naphthalocyanine compound shown by general formula (NP-1).
General formula (1)

General formula (NP-1)

(In the formula, M represents a metal atom. R ₂₈ and R ₂₉ may be absent. In some cases (= axial ligand type), each independently represents a hydrogen atom or a substituent. R _{4 to} R _27. Each independently represents a hydrogen atom or a substituent.) The photoelectric conversion material according to claim 1,
A photoelectric conversion material in which the naphthalocyanine compound has an axial ligand structure represented by the following general formula (NP-2).
General formula (NP-2)

(In the formula, M is any one of Si, Ge, and Sn, and R ^{1 to} R ²⁷ each independently represents a hydrogen atom or a substituent.) Said provided a photoelectric conversion film including a photoelectric conversion material according to claim 1 or 2, the first photoelectric conversion unit comprising a pair of electrodes facing each other across the photoelectric conversion film,
The photoelectric conversion element in which the photoelectric conversion film has a stacked structure of a layer made of the naphthalocyanine compound and a layer made of the squarylium compound. The photoelectric conversion element according to claim 3 , wherein
A photoelectric conversion element in which a bulk heterostructure film of the naphthalocyanine compound and the squarylium is formed on the photoelectric conversion film. The photoelectric conversion element according to claim 3 or 4 , wherein the layer made of the squarylium compound has a thickness of 20 nm or less. The photoelectric conversion device according to any one of 5 the claim 3, wherein the absorption peak wavelength of the first photoelectric conversion unit is at 650nm or more and visible light in a wavelength region 400 nm to 600 nm 50% or more transmittance A photoelectric conversion element. The photoelectric conversion element according to any one of claims 3 to 6 ,
The first photoelectric conversion unit includes a semiconductor substrate stacked above,
A second photoelectric conversion unit that has an absorption peak of an absorption spectrum in a range including a visible region and an infrared region in the visible region and generates a charge corresponding to the absorbed light is interposed between the semiconductor substrate and the first photoelectric conversion unit. A photoelectric conversion element provided with at least one. The photoelectric conversion element according to claim 7 ,
The semiconductor substrate includes an accumulation unit that accumulates charges generated in each of the first photoelectric conversion unit and the second photoelectric conversion unit, and a signal reading unit that reads a signal corresponding to the charges accumulated in the accumulation unit. A photoelectric conversion element provided. The photoelectric conversion element according to any one of claims 3 to 6 ,
The first photoelectric conversion unit includes a semiconductor substrate stacked above,
A photoelectric conversion element comprising at least one second photoelectric conversion unit in the semiconductor substrate that has an absorption peak of an absorption spectrum in a range including a visible region and an infrared region in the visible region, and generates a charge corresponding to the absorbed light. The photoelectric conversion element according to claim 9 , wherein
A photoelectric conversion element, wherein the semiconductor substrate includes an accumulation unit that accumulates electric charges generated in the first photoelectric conversion unit, and a signal reading unit that reads out a signal corresponding to the electric charges accumulated in the accumulation unit. The photoelectric conversion element according to claim 7 or 9 , wherein
A plurality of the second photoelectric conversion units;
A photoelectric conversion element in which the plurality of second photoelectric conversion units have absorption peaks at different wavelengths. The photoelectric conversion element according to claim 11 ,
The photoelectric conversion element in which the plurality of second photoelectric conversion units are stacked in a light incident direction to the first photoelectric conversion unit. The photoelectric conversion element according to 10 above claim 3,
A plurality of the second photoelectric conversion units;
The photoelectric conversion elements in which the plurality of second photoelectric conversion units have absorption peaks at different wavelengths and are arranged in a direction perpendicular to a light incident direction to the first photoelectric conversion unit. The photoelectric conversion element according to claim 12 or 13 , wherein
Three second photoelectric conversion units are provided,
The three second photoelectric conversion units absorb an R photoelectric conversion unit that absorbs light in the red wavelength range, a G photoelectric conversion unit that absorbs light in the green wavelength range, and B that absorbs light in the blue wavelength range. A photoelectric conversion element which is a photoelectric conversion unit. The photoelectric conversion element according to 14 above claim 3,
The photoelectric conversion element with which the said photoelectric conversion part and the said 2nd photoelectric conversion part have overlapped in planar view so that the light which permeate | transmitted the said 1st photoelectric conversion part may inject into the said 2nd photoelectric conversion part. The photoelectric conversion element according to the claim 3 to 15,
A photoelectric conversion element, wherein a charge blocking layer for preventing charge injection from the electrode is provided on at least one of an upper layer and a lower layer of the photoelectric conversion film. The photoelectric conversion device according to any one of claims 3 to 16 , wherein
The photoelectric conversion element whose absorption peak wavelength of a said 1st photoelectric conversion part is 650 nm or more, and the absorptance in this absorption peak wavelength is 50% or more. The photoelectric conversion device according to any one of claims 7 , 9 , 11 to 15 ,
The photoelectric conversion element whose said 2nd photoelectric conversion part has the transmittance | permeability of light with a wavelength range of 400 nm-600 nm is 75% or more. The photoelectric conversion element according to the claim 3 to 18,
A photoelectric conversion element in which at least one of the pair of electrodes is a conductive thin film having a light transmittance of 95% or more in a wavelength region of 400 nm to 900 nm. The photoelectric conversion element according to the claim 3 to 18,
A photoelectric conversion element in which at least one of the pair of electrodes is a transparent conductive thin film having a light transmittance of 95% or more in a wavelength region of 400 nm to 900 nm. A solid-state imaging device where the photoelectric conversion elements are arranged in an array according to the claim 3 to 20.

Images