KR20110002694A - Near infrared photo-detector and the fabrication method thereof - Google Patents

Abstract

PURPOSE: A near infrared ray sensor and a method for manufacturing the same are provided to obtain high photosensitive efficiency by effectively separating an electron-hole pair generated from the absorption of near infrared ray. CONSTITUTION: An electron-hole pair is generated in a photosensitive nano-particle by absorbing near infrared ray. Electrons generated in the photosensitive nano-particle are voluntarily moved according to the conductive band of a semiconductor layer(30). Holes generated in the photosensitive nano-particle are voluntarily moved according to the valance band of a hole conductive layer(60). A recombination blocking layer(50) is formed between the semiconductor layer and the hole conductive layer. The recombination blocking layer blocks the recombination of the electron and the hole respectively moved to the conductive band of the semiconductor layer and the valence band of the hole conductive layer.

Description

Near-infrared sensing element and its manufacturing method {Near Infrared Photo-Detector and the Fabrication Method Thereof}

The present invention relates to a near-infrared sensing element having a novel structure for detecting near-infrared rays, and a method for manufacturing the same, which is manufactured by simple coating, and can be manufactured with a large area and a flexible substrate, and can mass-produce high-quality near-infrared sensing elements in a short time. Purity of the photosensitive material which effectively separates the electron-hole pairs generated by light, effectively inhibits recombination of the generated electron-hole pairs, and absorbs near infrared rays to produce electron and hole pairs. The present invention relates to a near-infrared sensing device having a structure that is insensitive to a near-infrared sensing environment including temperature and minimizes the influence of defects.

Near Infrared (Near Infrared or shortwave Infrared, or NIR) refers to light in the wavelength range of about 700 to 2000 nm, and can be observed at high sensitivity, high resolution, and even in dark nights. Although it has good permeability (day-to-night imaging), no cryogenic cooling for device operation, and low-cost general visible light for system configuration, it can be used as it is.

NIR sensing devices that detect light in the 700 to 2000 nm range are used in a variety of applications, including security devices, medical devices, and non-destructive testing devices, and are equipped with conventional silicon-based visible light sensing devices for higher sensitivity and wider sensing Development of new fusion image sensors with a range is expected.

First, NIR sensing devices can be divided into photovoltaic and photoconductive devices according to the presence or absence of externally applied voltage.Infrared sensing devices including NIR are generally used as single crystal thin film semiconductor devices. have. Forms using quantum wells such as quantum wells or quantum dots (Japanese Patent Publication 2008-187022, Japanese Patent Publication 2008-187003, Japanese Patent Publication 2008-147521, Korean Patent Publication 2001-0054216, Korean Patent Publication 2000-0061903, US Patent Publication 2006-0266998, U.S. Patent Application Publication No. 2006-0138396) or a device (Korea Patent Publication No. 2006-0093445) that combines a quantum structure and a high electron mobility transistor (HEMT) has been proposed. While the sensing device manufactured based on such a single crystal thin film semiconductor has excellent performance, the manufacturing process is complicated and difficult and expensive due to the use of high vacuum equipment.

Research of NIR sensing devices using functional chemical materials is a method of mixing a quantum dot and a conductive polymer as a photosensitive absorber or alternately stacking two material layers, a light absorbing layer and a polymer conductive layer (International Patent 2007) / 118815). The device of this type has low photoelectric conversion efficiency in the NIR region. Recently, a sensing device of a method in which a colloidal nanoparticle in solution is directly coated between two electrodes has been reported. However, this method has a disadvantage in that an external power source is required because a voltage must always be applied from the outside.

The object of the present invention is to eliminate the need for external power supply for light sensing, to effectively separate the electron-hole pairs generated by the light, to effectively recombine the generated electron-hole pairs, to suppress the response characteristics, It provides a near-infrared sensing device that is insensitive to the near-infrared sensing environment including temperature, and minimizes the effects of purity and defects of photosensitive materials that absorb near-infrared rays to generate electron and hole pairs. To provide a method for manufacturing a near-infrared sensing element that does not require strict process control during manufacturing, can be manufactured in large areas, can be integrated into a flexible substrate, and can be mass-produced in a short time.

Hereinafter, a near infrared ray sensing element and a manufacturing method of the present invention will be described in detail with reference to the accompanying drawings. The drawings introduced below are provided by way of example in order to fully convey the spirit of the present invention to those skilled in the art, may be exaggerated for clarity of understanding, configurations other than the core configuration may not be shown. The present invention is not limited to the drawings presented below, but may be embodied in other forms, and like reference numerals denote like elements throughout the specification.

At this time, if there is no other definition in the technical terms and scientific terms used, it has a meaning commonly understood by those of ordinary skill in the art to which the present invention belongs, the gist of the present invention in the following description and the accompanying drawings Descriptions of well-known functions and configurations that may be unnecessarily blurred are omitted.

The near-infrared sensing device according to the present invention includes a photosensitive nanoparticle that absorbs near infrared (Near Infrared or shortwave Infrared) to generate an electron-hole pair, a semiconductor layer providing an electron transport path, a hole conducting layer for providing a hole transport path, It is characterized by including a recombination preventing layer provided between the semiconductor layer and the hole conducting layer to suppress the recombination of the electron-hole, in detail electrons generated from the photosensitive nanoparticles are spontaneously moved to the semiconductor layer, Holes generated in the sensitized nanoparticles are spontaneously transferred to the hole conducting layer, and a recombination preventing layer is formed at the interface where the hole conducting layer and the semiconductor layer contact each other to form an energy barrier based on electrons. It is characterized by the disappearance by recombination of the.

More specifically, the electrons generated from the photosensitive nanoparticles are transferred to the semiconductor layer by the difference in the conduction band minimum energy level between the semiconductor layer and the photosensitive nanoparticles in contact with the photosensitive nanoparticles. The holes generated in the photosensitive nanoparticles are spontaneously moved, and the hole conduction is caused by a difference in the maximum energy level between the hole conduction layer and the photosensitive nanoparticles in contact with the photosensitive nanoparticles. Moving spontaneously into the valence band of the layer, provided between the semiconductor layer and the hole conducting layer, the conduction band minimum energy level being the conduction band minimum energy level of the semiconductor layer electrons and the hole conducting layer moved to the conduction band of the semiconductor layer by a recombination preventing layer comprising a semiconductor material larger than It is characterized in that inhibit the recombination of a hole moves as the former.

Preferably, the near-infrared sensing element according to the present invention further comprises a transparent electrode and a counter electrode, the transparent electrode is provided below the semiconductor layer, and the counter electrode is provided above the hole conductive layer. More preferably, the near-infrared sensing element according to the present invention further comprises a transparent insulating substrate, and a transparent insulating substrate is provided below the transparent electrode. At this time, the counter electrode and the transparent electrode may be electrically connected through an external electric circuit including an external load.

1 is a cross-sectional view of the near infrared sensing element according to the present invention. As shown in FIG. The semiconductor layer 30 is provided, and the photosensitive nanoparticles 40 are provided in contact with the semiconductor layer 30, and the photosensitive nanoparticles 40 are contacted with the photosensitive nanoparticles 40 on the semiconductor layer 30. A hole conducting layer 60 is provided to provide a movement path, and an energy barrier based on conduction band electrons of the semiconductor layer 30 is provided between the semiconductor layer 30 and the hole conducting layer 60. Recombination prevention layer 50 is formed to form a.

In the photoelectron-light hole generated by the photosensitive nanoparticles 40 by absorbing near infrared rays, the photoelectrons are driven by the difference in the conduction band minimum energy level between the semiconductor layer 30 and the photosensitive nanoparticles 40. Spontaneously moved from the 40 to the semiconductor layer 30, the light hole is the photosensitive nanoparticles (the photosensitive nanoparticles with a driving force difference of the valence band maximum energy level between the hole conducting layer 60 and the photosensitive nanoparticles 40 40 voluntarily moves to the hole conducting layer (60). The photoelectrons spontaneously transferred to the semiconductor layer 30 are prevented from moving to the interface of the hole conducting layer 60 by the energy barrier by the recombination preventing layer 50, thereby recombining the separated light holes and photoelectrons. Extinction is suppressed.

In particular, the recombination preventing layer 50 has a conduction band minimum energy level greater than the conduction band minimum energy level of the semiconductor layer 30, and the semiconductor layer 30. An energy barrier is formed by the difference between the minimum energy level of the conduction band of c) and the conduction band minimum energy level of the recombination prevention layer 50.

More specifically, the recombination preventing layer 50 is made of the same semiconductor material as the semiconductor layer 30, and the conduction band of the semiconductor layer 30 is formed by a quantum confinement effect or a phase. band has a conduction band minimum energy level that is greater than the minimum energy level.

In this case, the phase refers to a crystal structure of a solid that affects an energy band diagram of a material including an energy band gap, a conduction band minimum energy level, and a valence band maximum energy level. The crystal structure includes amorphous with short range order, and includes thermodynamically stable or unstable crystalline phase with long range order.

In this case, the recombination preventing layer 50 has a conduction band minimum energy level greater than the conduction band minimum energy level of the semiconductor layer 30 due to the quantum confinement effect. Means that the energy band diagram varies depending on the size of the semiconductor material constituting the recombination preventing layer 50 on at least one axis (at least one axis among orthogonal three axes).

In the near-infrared sensing device according to the present invention, in the case of having a conduction band minimum energy level larger than the conduction band minimum energy level of the semiconductor layer 30 due to the quantum confinement effect, As shown in FIG. 1A, the recombination prevention layer 50 preferably includes semiconductor nanoparticles 51 having a radius smaller than a bore radius.

In the near-infrared sensing device according to the present invention, in the case of having a conduction band minimum energy level larger than the conduction band minimum energy level of the semiconductor layer 30 by a phase. As shown in FIG. 1B, the recombination preventing layer 50 is the same semiconductor as the semiconductor layer 30 in an amorphous phase.

Although the recombination preventing layer 50 is composed of the semiconductor nanoparticles 51 in the drawings except for FIG. 1 (b) in the present invention, the semiconductor nanoparticles ( It is apparent that the anti-recombination layer 50 composed of 51 may be replaced by the anti-recombination layer 50 composed of an amorphous semiconductor.

1 (b) and 1 (c) are other examples showing cross-sectional views of the near infrared ray sensing element according to the present invention.

FIG. 1B illustrates an example in which the semiconductor layer 30 has a large specific surface area due to regular or irregular surface irregularities and a recombination preventing layer 50 is formed of an amorphous semiconductor 52. (c) shows that the semiconductor nanoparticles 51 have a large specific surface area due to the pores opened by the semiconductor layer 30 to the porous semiconductor layer 30 and have a bandgap energy greater than that of the semiconductor layer 30 due to the quantum confinement effect. ) Shows an example in which the recombination prevention layer 50 is configured.

When surface irregularities are formed as shown in FIG. 1B, the photosensitive nanoparticles 40 are provided to be in contact with the uneven surface of the semiconductor layer 30, and the recombination prevention layer 50 is formed on the photosensitive nanoparticles 40. It is provided in contact with the surface of the semiconductor layer 30 is not screened by.

In the case of having open pores as shown in FIG. 1C, the photosensitive nanoparticles 40 are provided in contact with the semiconductor layer 30 in the open pores and the upper surface of the porous semiconductor layer 30, and the recombination preventing layer ( 50 is formed in open pores not screened by the photosensitive nanoparticles 40, similarly to the recombination prevention layer 50 shown in the lower part of FIG. 1 (c), the semiconductor nanoparticle layer of FIG. The semiconductor layer 30 is provided on the surface and the upper surface thereof.

As shown in FIG. 1C, when the semiconductor layer 30 is a porous semiconductor layer having open pores, the hole conducting layer 60 is preferably a hole conducting organic material, and the semiconductor layer 30 It is preferable to cover the upper surface of the semiconductor layer 30 by filling the pores present.

With the recombination preventing layer 50 according to the present invention, the semiconductor layer 30 having surface irregularities similar to those of FIG. 1 (b) or the porous semiconductor layer 30 having open pores similar to those of FIG. The semiconductor layer has a very large specific surface area, so that the content of the photosensitive nanoparticles 40 can be increased, and the photosensitive characteristics are excellent, and the device can be miniaturized.

1 illustrates an embodiment according to the core idea of the present invention, and the technical idea of the present invention will be described in detail with reference to FIG. 2.

2 is based on the energy of the vacuum phase electrons of the energy band semiconductor layer 30, the photosensitive nanoparticles 40, the anti-recombination layer 50 and the hole conducting layer 60 of the near-infrared sensing element according to the present invention (0). An energy band diagram is shown.

2 (a) is an energy band diagram between the semiconductor layer 30, the photosensitive nanoparticles 40, and the hole conducting layer 60 in the near-infrared sensing device according to the present invention, and FIG. As shown for the sake of understanding, an energy band diagram between the semiconductor layer 30 and the hole conducting layer 60 when the recombination prevention layer 50 according to the present invention is not present, and FIG. Energy band diagram between semiconductor layer 30-anti-recombination layer 50-hole conductive layer 60 when 50 is present between semiconductor layer 30 and hole conductive layer 60.

As shown in FIG. 2 (a), in the near-infrared sensing device according to the present invention, the semiconductor layer 30 includes band gap energy (Eg (SC), eV) of the semiconductor layer 30. ) Is greater than the band gap energy (Eg (PS), eV) of the photosensitive nanoparticle 40, and the minimum energy level Ec (SC) of the conduction band of the semiconductor layer 30. eV) is the semiconductor layer 30 lower than the conduction band minimum energy level Ec (PS), eV of the photosensitive nanoparticle 40.

 Accordingly, photoelectrons in the photoelectron-light hole pairs generated by the photosensitive nanoparticles 40 by absorbing near infrared rays (700 to 2000 nm) are transferred from the photosensitive nanoparticles 40 to the conduction band of the semiconductor layer 30. By moving spontaneous to the outside of the device through the transparent electrode 10, the light hole is moved to the counter electrode 70 by the hole conductive layer 60 in contact with the photosensitive nanoparticles (40) Will move outside.

More specifically, the conduction band minimum energy level Ec (SC) of the semiconductor layer 30 is lower than the conduction band minimum energy level Ec (PS) of the photosensitive nanoparticle 40 and the semiconductor particles 31. ) Satisfies the following expression 1.

(Relationship 1)

0 <| Ec (SC) -Ec (PS) | ≤ Eg (PS)

(Eg (PS) is the bandgap energy (eV) of the photosensitive nanoparticles, Ec (SC) is the conduction band minimum energy level of the semiconductor layer, and Ec (PS) is the conduction band of the photosensitive nanoparticles). Is the minimum energy level.)

The conduction band minimum energy level Ec (SC) of the semiconductor layer 30 is lower than the conduction band minimum energy level Ec (PS) of the photosensitive nanoparticle 40, and the conduction band of the semiconductor layer 30 is As the minimum energy level (Ec (SC)) satisfies Equation 1 above, the trap state has the energy level of the ban band (energy vs. bandgap) generated by the purity, defects, etc. of the photosensitive nanoparticles. Effects can be eliminated and thermal noise can be minimized.

As shown in FIG. 2 (a), in the near-infrared sensing device according to the present invention, the hole conducting layer 60 is the minimum energy level Ec (H) of the conduction band of the hole conducting layer 60. , eV is higher than the conduction band minimum energy level Ec (PS) of the photosensitive nanoparticle 40, and the valence band maximum energy level of the hole conducting layer 60 is Ev ( H), eV) is a hole conducting layer 60 higher than the valence band maximum energy level (Ev (PS), eV) of the photosensitive nanoparticle 40.

At this time, as described above, the energy level of the hole conducting layer 60 based on the photosensitive nanoparticles 40 is described as the reference (0) based on the energy of the electron in the vacuum phase, and accordingly, near infrared rays (700 to 2000 nm). Absorbing), light holes in the photoelectron-light hole pair generated in the photosensitive nanoparticles 40 moves spontaneous from the photosensitive nanoparticles 40 to the hole conducting layer 60. It moves to the outside through the counter electrode 70 provided on the conductive layer 60.

The photosensitive nanoparticle 40 is a material capable of absorbing near infrared rays to generate photoelectron-holes. The band gap energy (Eg (PS), eV) of the photosensitive nanoparticle 40 is represented by Equation 2 below. It is desirable to be satisfied.

(Relationship 2)

0.6 (eV) ≤ Eg (PS) ≤ 1.7 (eV)

(The Eg (PS) is the bandgap energy (eV) of the photosensitive nanoparticles.)

When the anti-recombination layer 50 according to the present invention is not present, the semiconductor layer 30 provides a movement path of electrons in the electron-hole pair generated in the photosensitive nanoparticles 40 and provides a movement path of holes. The hole conductive layer 60 is in contact with each other in the region where the photosensitive nanoparticles 40 are not formed to form an interface.

As shown in FIG. 2B, electrons and holes spontaneously separated from each other by the semiconductor layer 30 and the hole conduction layer 60 in the photosensitive nanoparticles 40 are formed in the semiconductor layer 30 and the hole conduction. At the interface where the layers 60 contact, they recombine and disappear.

As shown in FIG. 2 (c), when the anti-recombination layer 50 is present between the semiconductor layer 30 and the hole conducting layer 60, the electrons generated from the photosensitive nanoparticles 40 are separated from each other. After the holes are spontaneously separated from each other by the semiconductor layer 30 and the hole conducting layer 60, the energy barrier is present in the extinction due to the recombination of electrons and holes.

In detail, as the conduction band minimum energy level Ec (RC) of the recombination prevention layer 50 is higher than the conduction band minimum energy level Ec (SC) of the semiconductor layer 30, the anticombination layer 50 in the semiconductor layer 30. In order to move the electrons to (), the energy barrier (E barrier of FIG. 2 (c)), which is the difference in conduction band minimum energy level between the recombination preventing layer 50 and the semiconductor layer 30, must be overcome, With this difficulty, extinction due to recombination of electrons and holes is also effectively suppressed.

Since the recombination prevention layer present at the interface between the electron conduction layer and the hole conduction layer, which provides the movement paths of the electrons and holes generated in the photosensitive material, is also in contact with the photosensitive nanoparticles that absorb the light and generate photoelectrons and holes, The recombination preventing layer 50 is the semiconductor layer 30 so as to act as a medium for contacting the photosensitive nanoparticles, which are attached to the photosensitive nanoparticles but not in direct contact with the electron conductive layer, with the electron conductive layer. It is preferable to control the size of the energy barrier by a phase or a quantum confinement effect of the recombination prevention layer 50, which is composed of the same semiconductor material as).

Preferably, the transparent electrode 10 is made of an electrically conductive transparent material that is ohmic bonded to the semiconductor layer 30, and the counter electrode 70 is made of a metal material that is ohmic bonded to the hole conductive layer 60. It is preferable to be.

3 is a cross-sectional view of a near-infrared sensing device according to the present invention. The semiconductor layer 30 is a porous semiconductor layer 30 having open pores, and the porous semiconductor layer 30 is a plurality of semiconductors. Particles 31, the photosensitive nanoparticles 40 are provided in contact with the semiconductor particles 31, the hole conductive layer 60 fills the empty space between the semiconductor particles 31 and at the same time porous semiconductor layer A recombination prevention layer 50, which covers the upper portion of 30 and is composed of semiconductor nanoparticles 51, is provided between the semiconductor particles 31 and the hole conducting layer 60 filling the open pores of the porous semiconductor layer 30. .

In this case, the semiconductor particles 31, the recombination preventing layer 50 and the hole conducting layer 60, as well as satisfying the above-described energy band conditions based on the Figure 2, the constituent of the porous semiconductor layer 30 The semiconductor particles 31 preferably have a structure in which electrons generated from the photosensitive nanoparticles 40 are continuously connected to each other so that the electrons are well transmitted to the transparent electrode 10.

As shown in FIG. 3, the near-infrared sensing device according to the present invention is provided with photosensitive particles 40 in the pores of the porous semiconductor layer 30 composed of the semiconductor particles 31 providing a path of electron transfer and a hole conducting layer. By having a configuration of a composite photosensitive layer filled with pores existing in the porous semiconductor layer 30 by (60), generation of photoelectron-light holes by near infrared rays, separation of photoelectron-light holes, and movement of the photoelectron-holes This single composite photosensitive layer is characterized in that it is provided with a recombination preventing layer 50 having an energy barrier restricting the movement of electrons between the semiconductor particles 31 and the hole conducting layer 60 and the semiconductor particles 31. ) Is not in direct contact with the hole conducting layer 60, preventing recombination of electron-holes and having a fast optical response characteristic.

Preferably, the anti-recombination layer 50 is made of the same semiconductor material as the semiconductor material of the semiconductor particles 31, and forms an energy barrier to electron movement by a phase or quantum confinement effect. In this case, when the energy barrier is formed by the phase, the recombination preventing layer 50 is formed of an amorphous phase of the same material as that of the semiconductor material of the semiconductor particles 31, and forms an energy barrier by the quantum confinement effect. In this case, as shown in FIG. 3, the recombination prevention layer 50 is composed of semiconductor nanoparticles 51 having a size smaller than the average particle diameter of the semiconductor particles 31.

Although the recombination prevention layer 50 composed of the semiconductor nanoparticles 51 is illustrated in FIG. 3, the recombination prevention layer 50 may be an amorphous semiconductor material as described above. It goes without saying that it contains the mixture which the semiconductor nanoparticle which has it mixed.

As shown independently in the lower part of FIG. 3, the recombination prevention layer 50 is a partially open film. In detail, a passage A through which electrons generated from the photosensitive nanoparticles 40 moves to the semiconductor particles 31 is shown. ), An open film having a passage B through which electrons move between the semiconductor particles 31, and a passage C through which electrons of the semiconductor particles 31 move to the transparent electrode 10.

The photosensitive nanoparticles 40 are provided in contact with the semiconductor particles 31 in the voids between the semiconductor particles 31, and as the specific surface area of the semiconductor particles 31 increases, the specific surface area of the semiconductor particles 31 decreases. The average diameter is preferably 10 to 500 nm, and the average diameter of the photosensitive nanoparticles 40 is smaller than that of the semiconductor particles 31 and has a size smaller than the bore radius. Substantially, the average diameter of the semiconductor nanoparticles 51 is 1 to 30 nm.

In addition, the thickness of the porous semiconductor layer 30 composed of the semiconductor particles 31 is preferably from 0.2 to 10 ㎛ in terms of high photoelectric efficiency, smooth photocurrent flow. When the thickness of the porous semiconductor layer 30 is less than 0.2 μm, the amount of the photosensitive nanoparticles 40 formed in the porous semiconductor layer 30 is reduced to reduce the efficiency of the device, and when the thickness is greater than 10 μm, the light is sensitive. Since the moving distance of the photocurrent generated from the nanoparticles 40 becomes long, there is a risk that the efficiency of the device is reduced.

4 is a cross-sectional view of the near-infrared sensing device according to the present invention when the semiconductor layer 30 is an open porous structure, the porous semiconductor layer 30 and the transparent electrode 10 It is an example that the semiconductor thin film 20 is further provided therebetween.

The semiconductor thin film 20 is made of the same material as the semiconductor material constituting the porous semiconductor layer 30, and is characterized in that the same semiconductor material as the semiconductor particles 31, the semiconductor thin film 20 is a transparent electrode 10 ) And the hole conductive layer 60 filling the voids present in the porous semiconductor layer 30 so that the hole conductive layer 60 does not come into contact with the transparent electrode 10. In this case, as shown in FIG. 4, it is preferable that a recombination prevention layer is formed between the semiconductor thin film 20 and the hole conductive layer 60.

The hole conductive layer 60 is formed to fill the pores existing in the porous semiconductor layer 30 and to cover the upper portion of the porous semiconductor layer 30, as shown in Figure 3 or 4 It is preferable that the semiconductor particles 31 constituting the porous semiconductor layer 30 and the counter electrode 70 do not contact each other by the reference numeral 60.

5 is a cross-sectional view showing another example of the infrared sensing element according to the present invention. As shown in FIG. 5, the infrared sensing element according to the present invention further includes an insulating transparent substrate 80 and the transparent electrode. (10) An insulating transparent substrate 80 is provided below.

As described above, the near-infrared device according to the present invention includes a semiconductor layer, a recombination preventing layer, a photosensitive nanoparticle, and a hole conducting layer satisfying the above-described energy level conditions based on FIG. 2.

For example, the photosensitive nanoparticles 40 may be selected from one or more of PbS, PbSe, PbTe, Cu ₂ S, HgTe, CoS, CoSe, NiS, MoS, MoSe, and a combination thereof.

The semiconductor layer 30 is selected from at least one of TiO ₂ , ZnS, SnO ₂ , WO _3, BaTiO ₃ , FeTiO ₃ , Ta ₂ O ₅ , Nb ₂ O ₅ , CdO, YFeO ₃ , ZrS _2, and combinations thereof. .

The recombination preventing layer 50 is at least one of amorphous TiO ₂ , ZnS, SnO ₂ , WO _3, BaTiO ₃ , FeTiO ₃ , Ta ₂ O ₅ , Nb ₂ O ₅ , CdO, YFeO ₃ , ZrS ₂ and composites thereof Is selected.

The anti-recombination layer 50 is TiO ₂ , ZnS, SnO ₂ , WO _3, BaTiO ₃ , FeTiO ₃ , Ta ₂ O ₅ , Nb ₂ O ₅ , CdO, YFeO ₃ , ZrS ₂ and the average radius is smaller than the bore radius At least one selected nanoparticle in the complex of.

The hole conducting layer 60 is P3HT (poly (3-hexylthiophene)), spiro-OMeTAD (2,2 ', 7,7'-tetrakis- (N, N-di-pmethoxyphenyl-amine) -9,9' -spirofluorene), MDMO-PPV (poly [2-methoxy-5- (3 ', 7'-dimethyloctyloxyl)]-1,4-phenylene vinylene), MEH-PPV (poly [2-methoxy-5- (2''-ethylhexyloxy) -p -phenylene vinylene]), P3OT (poly (3-octyl thiophene)), PPV (poly ( p -phenylene vinylene)), TFB (poly (9,9'-dioctylfluorene-co-N- ( 4-butylphenyl) diphenylamine), POT (poly (octyl thiophene)), PEDOT (Poly (3,4-ethylenedioxythiophene)), CuSCN (Copper (I) thiocyanate), CuI, CuPC (Copper Phthalocyanine) and one of them Is chosen.

The transparent electrode 10 may be formed of fluorine-containing tin oxide (FTO), indium doped tin oxide (ITO), ZnO, CNT (carbon nanotube), graphene, and the like. At least one is selected from the complexes of.

The counter electrode 70 is selected from one or more of gold, silver, platinum, palladium, copper, aluminum and a combination thereof.

In particular, the photosensitive nanoparticles 40 are PbS quantum dots, the semiconductor layer 30 is TiO ₂ , and the recombination prevention layer 50 is amorphous TiO ₂ , TiO ₂ nanoparticles, or a mixture thereof. The hole conducting layer 60 is 2,2 ', 7,7'-tetrakis- (N, N-di- p methoxyphenyl-amine) -9,9'-spirofluorene, and the transparent electrode 10 ) Is fluorine-containing tin oxide, and the counter electrode 70 is gold.

In this case, the photosensitive nanoparticle 40 is preferably attached to the semiconductor layer 30 by a linker having a hydrophilic terminal and a thiol group, and in detail, the linker has a terminal group as a carboxyl group or a hydroxyl group. Mercapto propionic acid, mercapto benzoic acid, mercapto succinic acid, or mercaptoalkoxysilane in which the and mercapto groups exist simultaneously.

Hereinafter, the high quality NIR sensor according to the present invention can be manufactured through a very simple and easy process such as simple coating and impregnation, can be manufactured with low cost equipment, and does not require strict process control during manufacturing and is manufactured in large areas. The method is possible, can be integrated into a flexible substrate, and can be mass-produced in a short time. In the above-described manufacturing method of the present invention, the spirit of the present invention described above is maintained based on FIG. 2, and description thereof is omitted in the following manufacturing method.

Method for manufacturing a near-infrared sensing element according to the present invention comprises the steps of: a) forming a porous semiconductor layer 30 by applying a slurry containing the semiconductor particles 31 to the transparent electrode 10; b) forming photosensitive nanoparticles 40 in contact with the porous semiconductor layer 30; c) applying a precursor solution containing a metal precursor to the porous semiconductor layer 30 provided with the photosensitive nanoparticles 40, followed by heat treatment to form a recombination prevention layer 50; d) forming a hole conducting layer 60 by applying an organic solution in which a hole conductive organic material is dissolved to the porous semiconductor layer 40 having the recombination preventing layer 50; And e) forming a counter electrode 70 on the hole conductive layer 60.

As shown in the process diagram of FIG. 6, the step a) includes: a1) forming the semiconductor thin film 20 over the transparent electrode 10 formed on the insulating transparent substrate 80 and a2) the semiconductor. And applying a slurry containing the semiconductor particles 31 on the thin film 20 to form the porous semiconductor layer 30.

The semiconductor particles 31 of the porous semiconductor layer 30 of step a) are metal oxides or metal sulfides, preferably TiO ₂ , ZnS, SnO ₂ , WO _3, BaTiO ₃ , FeTiO ₃ , Ta ₂ O ₅ , At least one selected from Nb ₂ O ₅ , CdO, YFeO ₃ , ZrS ₂ and composites thereof, more preferably TiO ₂ , SnO ₂ , WO _3, BaTiO ₃ , FeTiO ₃ , Ta ₂ O ₅ , Nb ₂ O ₅ , CdO, YFeO ₃ , and combinations thereof. It is preferable that the semiconductor thin film 20, the porous semiconductor layer 30, and the recombination prevention layer 50 are the same semiconductor material on the transparent electrode 10.

The slurry of step a) may be prepared by mixing the semiconductor particles 31, an organic binder for controlling porosity (eg, ethyl cellulose) and a liquid, and the liquid may be chemically reacted with the semiconductor particles 31. It can be removed by volatilization without reacting, and any liquid can be used as long as it provides fluidity and dispersibility so that the semiconductor particles 31 in the slurry are homogeneously distributed. For example, water or alcohol can be used. At this time, the porosity of the porous semiconductor layer 50 can be controlled by appropriately controlling the content of the semiconductor particles 31 and the content of the organic binder of the slurry.

The application of the slurry in step a) is carried out by screen printing, spin coating, bar coating, gravure coating, blade coating or roll coating. Roll coating), the thickness of the porous semiconductor layer 30 can be easily controlled by repeatedly applying the slurry.

After applying the slurry in step a) and removing the added liquid for slurry production, in order to improve the physical strength of the porous semiconductor layer 30 and to form the electron transport path more stably, the semiconductor particles 31 The heat treatment to form the neck may be additionally performed, and whether or not to be performed and the temperature should be appropriately determined in consideration of the size of the semiconductor particles 31 constituting the porous semiconductor layer 30.

  Step b) is performed by application of a dispersion (including a colloidal dispersion) in which the photosensitive nanoparticles 40 are dispersed or by a continuous chemical reaction method.

The photosensitive nanoparticle 40 is a material in which two or more elements are ion-bonded, and preferably, at least one selected from PbS, PbSe, PbTe, Cu ₂ S, HgTe, CoS, CoSe, NiS, MoS, MoSe, and a combination thereof. It is a substance.

Specifically, in step b), the photosensitive nanoparticle dispersion in the colloidal state is applied to the porous semiconductor layer 30 (colloid QD of FIG. 6) to form the photosensitive nanoparticles in the internal pores of the porous semiconductor layer 30. . Application of the photosensitive nanoparticle dispersion is carried out by impregnation, spin coating or spraying. By repeated application of the photosensitive nanoparticle dispersion, the amount of the photosensitive nanoparticles 40 formed in the porous semiconductor layer 30 can be easily controlled.

In detail, step b) is performed by a continuous chemical reaction method (SILAR of FIG. 6; Successive Ionic Layer Adsorption and Reaction, hereinafter SILAR). More specifically, the photosensitive nanoparticles are applied to the porous semiconductor layer 30 by alternately applying a precursor solution of a cation constituting the photosensitive nanoparticles 40 and a precursor solution of an anion constituting the photosensitive nanoparticles 40. Form. By applying the precursor solution of the cation and the precursor solution of the anion as a unit process, the amount of the photosensitive nanoparticles 40 formed in the porous semiconductor layer 30 can be easily controlled by repeating the unit process.

After step b), step c) to form the recombination prevention layer 50 is performed.

As described above, the recombination prevention layer 50 of step c) is characterized in that the same semiconductor material as the porous semiconductor layer 30, and is a metal oxide or metal sulfide, preferably the metal oxide or metal sulfide is TiO ₂ , At least one selected from ZnS, SnO ₂ , WO _3, BaTiO ₃ , FeTiO ₃ , Ta ₂ O ₅ , Nb ₂ O ₅ , CdO, YFeO ₃ , ZrS _2, and a combination thereof, and more preferably, the anti-recombination layer 50 ) Is one or more metal oxides selected from TiO ₂ , SnO ₂ , WO _3, BaTiO ₃ , FeTiO ₃ , Ta ₂ O ₅ , Nb ₂ O ₅ , CdO, YFeO ₃ , and composites thereof.

When the porous semiconductor layer 30 is a metal sulfide, the solution in which the metal precursor is dissolved and the solution in which the sulfur precursor is dissolved are sequentially applied to the porous semiconductor layer 30 or the solution containing the metal precursor and the sulfur precursor is added. After coating on the porous semiconductor layer 30 and heat treatment to form a recombination preventing layer 50 made of a metal sulfide of the same material as the semiconductor particles, when the porous semiconductor layer 30 is a metal oxide, the metal precursor is dissolved The solution is applied to the porous semiconductor layer 30 and then heat-treated to form a recombination preventing layer 50 made of a metal oxide of the same material as the semiconductor particles.

The coating of the precursor solution in step c) is performed by spin coating, spraying, or impregnation, and is performed by impregnating the precursor solution with the porous semiconductor layer 30 provided with the photosensitive nanoparticles 40 for homogeneous coating. It is preferable.

Preferably, the porous semiconductor layer 30 is a metal oxide, the precursor solution containing the metal precursor is applied to the porous semiconductor layer 30, and then heat treatment is performed, so that the same material as the semiconductor particles 31 A metal oxide is formed, and the heat treatment is characterized in that an amorphous metal oxide, a metal oxide nanoparticle having a bore radius or less, or a mixture thereof is formed.

In this case, the precursor solution includes not only the solution state of the metal precursor, but also the sol state of the metal precursor. The sol state includes a sol state by hydrolysis and condensation.

Preferably, the heat treatment is performed in an atmosphere in which oxygen is present, and an amorphous or crystalline metal oxide may be selectively prepared by controlling the temperature of the heat treatment.

Preferably, when preparing an amorphous metal oxide, the sol solution in which the metal precursor is hydrolyzed and condensation is applied, and a low-temperature heat treatment that is difficult to nucleate crystals is performed to perform amorphous metal. It is preferable to prepare oxides.

In detail, when the amorphous metal oxide is to be prepared, heat treatment is performed at a temperature range in which material transfer is possible through thermal activation to nucleation of crystals is suppressed. Heat treatment is carried out at a temperature, and more particularly heat treatment is carried out at a temperature of 100 to 130 ℃.

Preferably, when preparing a crystalline metal oxide, it is preferable to apply a precursor solution in which the metal precursor is dissolved, and to perform a heat treatment at a temperature at which nucleation of the crystal occurs to produce a crystalline metal oxide composed of polycrystalline nanoparticles. desirable. As is known, since the nucleation driving force of the metal oxide is larger than the growth driving force of the generated nucleus, heat treatment is performed by selecting a low temperature at which nucleation occurs and growth does not occur actively, thereby having an average size smaller than the bore radius. The recombination prevention layer 50 may be formed of polycrystalline particles.

Specifically, in the case of preparing a polycrystalline metal oxide having an average particle size smaller than the bore radius, heat treatment is performed at a temperature in which crystal nucleation occurs to a temperature range in which grain growth is suppressed. The heat treatment is carried out at a temperature of ℃, more specifically, the heat treatment is carried out at a temperature of 230 to 280 ℃.

As described above, the anti-recombination layer 50 according to the present invention includes a mixed phase of an amorphous phase and crystalline particles, and such a mixed phase may be formed in a region of 150 to 200 ° C., and the anti-recombination layer 50 configured as such a mixed phase Since the minimum energy level of the conduction band is greater than the minimum energy level of the conduction band of the porous semiconductor layer 30, of course, the spirit of the present invention is not departed.

The hole conductive layer 60 is preferably a hole conductive organic material for excellent bonding (contact) with the photosensitive nanoparticles 40 provided in the open pores of the porous semiconductor layer 30, the hole conductive layer 50 It is preferable to manufacture the spin-coated organic solution in which the silver hole conductive organic material is dissolved, followed by drying.

The hole conductive organic material is P3HT (poly (3-hexylthiophene)), spiro-OMeTAD (2,2 ', 7,7'-tetrakis- (N, N-di-pmethoxyphenyl-amine) -9,9'-spirofluorene) , MDMO-PPV (poly [2-methoxy-5- (3 ', 7'-dimethyloctyloxyl)]-1,4-phenylene vinylene), MEH-PPV (poly [2-methoxy-5- (2''-ethylhexyloxy ) -p -phenylene vinylene]), P3OT (poly (3-octyl thiophene)), PPV (poly ( p -phenylene vinylene)), TFB (poly (9,9'-dioctylfluorene-co-N- (4-butylphenyl) ) diphenylamine), POT (poly (octyl thiophene)), PEDOT (Poly (3,4-ethylenedioxythiophene)), CuSCN (Copper (I) thiocyanate), CuI, CuPC (Copper Phthalocyanine) and combinations thereof .

 The counter electrode 70 may be performed using physical vapor deposition or chemical vapor deposition, and is preferably manufactured by thermal evaporation.

As described above, step a) includes a1) forming the semiconductor thin film 20 over the transparent electrode 10 formed on the insulating transparent substrate, and a2) forming the semiconductor particles 31 on the semiconductor thin film 20. Forming a porous semiconductor layer 30 by applying a slurry containing the slurry; preferably, the semiconductor thin film 20 of step a1) is coated or physical / chemical vapor deposition. Spray Pyrolysis Deposition (SPD), Spin coating, Bar coating, Gravure coating, Blade coating, Roll coating Roll coating may be performed.

In particular, the photosensitive nanoparticles 40 are PbS quantum dots, the semiconductor layer 30 is TiO ₂ , and the recombination prevention layer 50 is amorphous TiO ₂ , TiO ₂ nanoparticles, or a mixture thereof. The precursor solution is a Ti-precursor solution, and the hole conducting layer 60 is 2,2 ', 7,7'-tetrakis- (N, N-di- p methoxyphenyl-amine) -9,9'- It is spirofluorene, the transparent electrode 10 is fluorine-containing tin oxide, and the counter electrode 70 is gold.

In particular, when preparing the amorphous TiO ₂ recombination preventing layer 50, the precursor solution contains a hydrolyzed and condensated Ti-precursor, and more particularly, the Ti-precursor is in water. Titanium alkoxide reacted by hydrolysis and condensation polymerization. The titanium alkoxide includes titanium (IV) iso-propoxide, titanium ethoxide, titanium butoxide, or mixtures thereof.

In this case, the manufacturing method according to the present invention further includes the step of forming a linker having a hydrophilic terminal and a thiol group in the porous semiconductor layer 30 after step a), the porous semiconductor in the solution containing the linker It is formed by impregnating the layer 30. The hydrophilic terminal of the linker is bonded to TiO ₂ of the semiconductor layer 30, and the thiol group is bonded to PbS quantum dots so that the photosensitive nanoparticles 40 are effectively formed in contact with the semiconductor layer 30. Specifically, the linker is a mercapto propionic acid, a mercapto benzoic acid, a mercapto benzoic acid, a mercapto succinic acid, a terminal group having a carboxyl group or a hydroxyl group and a mercapto group at the same time, Or mercaptoalkoxysilane.

The near-infrared sensing element according to the present invention has a high photosensitivity efficiency by effectively separating photoelectron-light holes generated by absorbing near-infrared rays and suppressing annihilation by recombination, and does not require the application of an external voltage for photoreduction of near-infrared rays. In addition to having a large specific surface area photosensitive area, the device can be miniaturized, and noise of photosensitive nanoparticles due to purity, defects, and inferiority can be minimized.

The method for manufacturing a near-infrared sensing element according to the present invention has advantages in that it can be manufactured by a very simple process such as impregnation, coating, low temperature heat treatment, and coating. The manufacturing process is not strict, and mass production, large area, and flexible substrate integration are easy. There is one advantage.

A photosensitive nanoparticle, a porous semiconductor layer, a recombination prevention layer, a PbS quantum dot, a TiO ₂ porous semiconductor layer, and a TiO ₂ recombination having a structure similar to that of FIG. 5 and satisfying the spirit of the present invention described above with reference to FIG. Protective layer, 2,2 ', 7,7'-tetrakis- (N, N-di- p methoxyphenyl-amine) -9,9'-spirofluorene, the specific manufacturing example and the photosensitive device manufactured The optical characteristic of this is explained in full detail.

(Porous semiconductor layer)

Fluorine-containing tin oxide formed on a glass substrate was used as a transparent electrode for ohmic contact, and gold was used as a counter electrode.

A glass substrate (8 ohms / sq, Pilkington, hereinafter FTO substrate) coated with fluorine-containing tin oxide ((FTO; F-doped SnO ₂ , hereinafter FTO)) was cut to a size of 25 x 25 mm and then partially etched by etching the end portion. FTO was removed.

Sprayed pyrolysis deposition (SPD) of 20 mM diisopropoxy titanium bis-acetylacetonate dissolved in ethanol on a partially etched FTO substrate with a dense structure of about 100 nm thick TiO ₂ thin film 20 was prepared.

After the paste was prepared by adding a predetermined amount of ethyl cellulose to TiO ₂ powder (Degussa, P25) having an average particle size of 25 nm on the FTO substrates 10 and 80 on which the TiO ₂ thin film 20 was formed, A porous TiO ₂ layer was prepared by screen printing. By controlling the number of times of screen printing, a porous TiO ₂ layer 30 having a thickness of about 800 nm was prepared. 7 is a scanning electron micrograph of the porous TiO ₂ layer 30 prepared on the TiO ₂ thin film 20 by screen printing.

(Photosensitive Nanoparticles)

In order to form PbS quantum dots 40, which are near-infrared sensitive particles, on the porous TiO ₂ layer 30, successive Ionic Layer Adsorption and Reaction (SILAR) using PbS quantum dot colloid or Pb precursor and S precursor is used. Was used.

When using SILAR method using a Pb precursor and S precursor, Pb and the 20 mM dissolved in methanol to a S precursor Pb (NO ₃₎ was used as the ₂ and 20 mM Na ₂ S, the porous TiO ₂ layer 20 mM Pb (NO ₃ ) Repeating the unit process three times to form a PbS quantum dot 40 in the porous TiO ₂ layer 30 by alternately dipping in ₂ and 20 mM Na ₂ S solution for 1 minute and washing with methanol as a unit process. It was.

In the case of using PbS quantum dot colloid (hereinafter, PbS CQD), PbO (4 mmol) and oleic acid were mixed with phenyl ether and reacted at 150 ° C. to produce Pb-oleate (Pb- PbS obtained by pyrolysis by high temperature injection method in which oleate) and trioctylphosphine (TOP) are added to S-powder and reacted with TOP powder, which is then rapidly injected into phenyl ether solution maintained at high temperature. PbS quantum dot was prepared by the method, and PbS quantum dot colloid (CQD, 0.3g / 50mL) stably dispersed in hexane was used. At this time, the average size of the PbS quantum dots was about 3 nm. A porous TiO ₂ layer to the PbS QDs colloid prepared by the above-described high temperature implantation method to form a photosensitive Yes nanoparticles on a porous TiO ₂ layer by dip coating (coating deep).

(Recombination Prevention Layer)

After forming PbS photosensitive particles 40 in the porous TiO ₂ layer 30 by PbS quantum dot colloid or SILAR method, a crystalline or amorphous TiO ₂ recombination prevention layer 50 was formed.

In order to prepare the crystalline recombination prevention layer 50, the porous TiO ₂ layer 30 on which the PbS photosensitive particles 40 were formed was immersed in an aqueous 30 mM TiCl ₄ solution for 30 minutes and heat-treated at 250 ° C. for 30 minutes in an air atmosphere. Was performed to form a crystalline TiO ₂ recombination prevention layer (50).

In order to prepare an amorphous anti-recombination layer 50, a small amount of water was added to a titanium (IV) iso-propoxide solution to form a hydrolysis condensation sol. TiO _x was used as a precursor solution, and the porous TiO ₂ layer 30 formed with PbS photosensitive particles 40 was deposited in 100 mM hydrolyzed condensed titanium (IV) iso-propoxide solution for 1 minute and then 110 ^o Heat treatment for 1 minute at C to form an amorphous TiO ₂ recombination prevention layer (50).

(Hole conducting layer)

After the recombination prevention layer 50 was formed, the hole conducting layer 60 was prepared by applying a solution in which a hole conducting organic material (HTM) was dissolved.

2,2 ', 7,7'-tetrakis- (N, N-di- p methoxyphenyl-amine) -9,9'-spirofluorene (spiro-OMeTAD; 2,2', the 7,7'-tetrakis- (N, N- di- p methoxyphenyl-amine) -9,9'-spirofluorene, below, spiro-OMeTAD) was used. Spiro-OMeTAD was spin-coated in a solution of 180 mg / mL in chlorobenzene at 1500-2500 rpm for 30 seconds to form a PbS photosensitive nanoparticle 40 and a recombination preventing layer 50. The pores inside the porous TiO ₂ layer were filled with a hole conductive organic material, and the top of the porous TiO ₂ layer was covered with the hole conductive organic material.

(Electrode)

After forming the hole conducting layer 60, Au was vacuum-deposited on the hole conducting layer 60 using a high vacuum (5x10 ^-6 torr or less) thermal evaporator, thereby charging Au with a thickness of about 70 nm. The pole was made.

In order to measure the optical characteristics of the manufactured near-infrared photosensitive device, 116mW, 980 nm laser was irradiated, and the photocurrent by laser irradiation was measured using a multimeter (Kethley model 2001). For transient response measurements, a 980nm laser diode was used, a laser power driver, a frequency modulator and function generator, and a low noise infrared photodiode. low noise IR photodiode was used. The output signal of the manufactured photosensitive device was measured from an oscilloscope to an input signal for laser power control, frequency control, and the like. delay time) was measured.

Hereinafter, the manufactured near-infrared photosensitive device is referred to as the crystal properties of the device / photosensitive nanoparticles manufacturing method / anti-recombination layer, depending on the method of forming PbS quantum dots (SILAR method or PbS CQD) and the crystallinity (crystalline or amorphous) of the recombination prevention layer. do. For example, in the SILAR method and the crystalline TiO ₂ anti-recombination layer, it is referred to as “device / SILAR / crystal”, and in the case of quantum dot colloid and amorphous TiO ₂ anti-recombination layer, it is referred to as “device CQD / amorphous”.

A near-infrared photosensitive device was manufactured in the same manner as in Preparation Example according to the present invention except that the recombination preventing layer was not formed as a comparative example. In this case, PbS quantum dots were formed by the SILAR method. A photosensitive device of Comparative Example in which no recombination preventing layer is present is referred to as "device / SILAR".

The photosensitive characteristics and transient response characteristics of each device / SILAR / crystalline, device / CQD / amorphous, and comparative device / SILAR according to the present invention are summarized in Table 1 below.

(Table 1)

The transient response was the slowest at 100-200 ms for devices / SILAR without recombination layer, 1.5 ms for device / SILAR / crystalline and 50 ms for device / CQD / amorphous It can be seen that improved.

In addition, it can be seen that the recombination of the photocurrent and the light holes generated in the photosensitive nanoparticles is effectively suppressed, thereby increasing the photocurrent. In this case, it can be seen that it is preferable that a crystalline recombination prevention layer is used in a field where transient response characteristics are more important and an amorphous recombination prevention layer is used in a field where sensitivity is more important, depending on the purpose of utilizing the photosensitive device.

In the device / CQD / amorphous photosensitive device, PbS quantum dots were formed on the porous semiconductor layer 30 by using a linker of 3-mercaptopropionic acid having a hydrophilic group, a carbonyl group and a thiol group as a terminal. In detail, the porous TiO ₂ layer was immersed in a 25% 3-mercaptopropionic acid solution for 2 hours, washed with alcohol to attach a linker to the surface of the porous TiO ₂ layer, and then PbS quantum dots in the same manner as in Preparation Example. PbS quantum dots were formed using a colloid, and an amorphous recombination prevention layer was formed using a hydrolysis condensation reaction titanium (IV) iso-propoxide solution. The device into which the linker was introduced is referred to as device / (L) CQD / amorphous, and the photosensitive characteristics and transient response characteristics are summarized in Table 2 below.

(Table 2)

8, 9, 10, and 11 are diagrams showing the results of measuring transient response characteristics of device / SILAR / crystalline, device / CQD / amorphous, device / (L) CQD / amorphous, and device / SILAR as a comparative example, respectively. .

In the present invention as described above has been described by the embodiments and the limited embodiments and drawings, which is provided only to help a more general understanding of the present invention, the present invention is not limited to the above embodiments, the present invention belongs to Many modifications and variations are possible in the art to those skilled in the art.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and all of the equivalents or equivalents of the claims as well as the claims to be described later will belong to the scope of the present invention. .

1 is a configuration diagram showing a cross-sectional view of a near infrared ray sensing element according to the present invention,

FIG. 2 is an energy band diagram of energy of vacuum phase electrons of semiconductor particles, photosensitive nanoparticles, recombination prevention layer, and hole conduction layer of a near infrared ray sensing device according to the present invention as reference (0).

3 is a cross-sectional view showing another example of an infrared sensing element according to the present invention;

4 is a cross-sectional view showing another example of an infrared sensing element according to the present invention;

5 is a cross-sectional view showing another example of an infrared sensing element according to the present invention;

6 is a process diagram illustrating a method of manufacturing an infrared sensing element according to the present invention,

7 is a scanning electron micrograph of the porous TiO ₂ layer prepared on the TiO ₂ thin film by screen printing,

8 is a diagram showing the results of transient response characteristics of the device / SILAR / crystalline,

9 is a diagram showing the results of transient response characteristics of the device / CQD / amorphous,

FIG. 10 shows the results of transient response characteristics of device / (L) CQD / amorphous.

11 is a diagram showing the results of transient response characteristics of the device / SILAR as a comparative example.

* Description of the symbols for the main parts of the drawings *

10 transparent electrode 20 semiconductor thin film

31 semiconductor particle 30 semiconductor layer

40: photosensitive nanoparticles 50: recombination prevention layer

51: semiconductor nanoparticle 60: hole conductive layer

70 counter electrode 80 transparent substrate

Claims (16)

Absorbs near-infrared rays to form electron-hole pairs in photosensitive nanoparticles, The electrons generated from the photosensitive nanoparticles spontaneously move to the conduction band of the semiconductor layer by the difference in the conduction band minimum energy level between the semiconductor layer and the photosensitive nanoparticles in contact with the photosensitive nanoparticles. , The holes generated in the photosensitive nanoparticles are in the valence band of the hole conducting layer by the difference in the valence band maximum energy level between the hole conducting layer and the photosensitive nanoparticles in contact with the photosensitive nanoparticles. Move voluntarily, A semiconductor material disposed between the semiconductor layer and the hole conductive layer, the semiconductor material including a semiconductor band having a minimum energy level of a conduction band greater than a minimum energy level of a conduction band of the semiconductor layer. A near-infrared sensing element according to claim 1, wherein recombination of the electrons moved to the conduction band of the semiconductor layer and the holes moved to the valence band of the hole conduction layer is suppressed by the recombination preventing layer. The method of claim 1, The recombination prevention layer is made of the same semiconductor material as the semiconductor layer, and has a conduction band larger than the conduction band minimum energy level of the semiconductor layer due to a quantum confinement effect or phase. conduction band) A near-infrared sensing element characterized by having a minimum energy level. 3. The method of claim 2, The recombination prevention layer is a near-infrared sensing element, characterized in that consisting of semiconductor nanoparticles of smaller radius than the bore radius. 3. The method of claim 2, And the recombination preventing layer is an amorphous phase. The method of claim 3, wherein The near infrared ray sensing element further includes a transparent electrode and a counter electrode, The semiconductor layer is provided on the transparent electrode and is a porous semiconductor layer having open pores, The photosensitive nanoparticles are provided in contact with the semiconductor layer in the pores of the semiconductor layer, The hole conductive layer is provided to fill the pores existing in the semiconductor layer and contact the photosensitive nanoparticles, and cover the upper portion of the semiconductor layer, The recombination preventing layer is provided between the semiconductor layer and the hole conductive layer, The counter electrode is a near-infrared sensing element, characterized in that provided on the hole conductive layer. 3. The method of claim 2, The bandgap energy (Eg) of the semiconductor layer is greater than the bandgap energy (Eg) of the photosensitive nanoparticles, and the minimum energy level of the conduction band of the semiconductor layer is the conduction band of the photosensitive nanoparticles. Less than the minimum energy level, The conduction band minimum energy level of the hole conducting layer is greater than the conduction band minimum energy level of the photosensitive nanoparticle, and the valence band maximum energy level of the hole conducting layer is the photosensitive nano. A near-infrared sensing element, characterized in that it is greater than the maximum energy level of the valence band of the particle. 3. The method of claim 2, The photosensitive nanoparticles are near infrared sensing element, characterized in that the PbS. The method of claim 7, wherein The semiconductor layer and the recombination preventing layer are each TiO ₂ , and the hole conducting layer is 2,2 ′, 7,7′-tetrakis- (N, N-di- p methoxyphenyl-amine) -9,9 ′. spiro fluorene; near-infrared detection device, characterized in that (spiro- OMeTAD 2,2 ', 7,7'- tetrakis- (N, N-di- p methoxyphenyl-amine) -9,9'-spirofluorene). The method of claim 8, The photosensitive nanoparticle is a near-infrared sensing element, characterized in that attached to the semiconductor layer by a linker (linker) having a hydrophilic terminal and a thiol group. A method for manufacturing a near infrared ray sensing element according to any one of claims 1 to 9, a) forming a porous semiconductor layer by applying a slurry containing semiconductor particles on the transparent electrode; b) forming photosensitive nanoparticles to contact the porous semiconductor layer; c) applying a precursor solution containing a metal precursor to the porous semiconductor layer provided with the photosensitive nanoparticles, followed by heat treatment to form a recombination prevention layer; d) forming a hole conductive layer by applying an organic solution in which a hole conductive organic material is dissolved to the porous semiconductor layer provided with the recombination prevention layer; And e) forming a counter electrode on the hole conductive layer; Method of manufacturing a near-infrared sensing element comprising a. The method of claim 10, The semiconductor particle of step a) is a metal oxide, and a metal oxide of the same material as that of the semiconductor particle is formed by the heat treatment of step c), and the metal oxide has an amorphous metal oxide or a metal having a bore radius or less. A method of manufacturing a near-infrared sensing element, wherein an oxide nanoparticle or a mixture thereof is formed. The method of claim 11, b) step is a method of manufacturing a near-infrared sensing element, characterized in that performed by the application of the colloidal photosensitive nanoparticle dispersion. The method of claim 12, The photosensitive nanoparticles of step b) is a substance in which two or more elements are ion-bonded, and step b) alternately applies a precursor solution of a cation constituting the photosensitive nanoparticles and a precursor solution of anion constituting the photosensitive nanoparticles. A method of manufacturing a near infrared ray sensing element, characterized in that performed. The method of claim 11, Step a) is applied to screen printing, spin coating, bar coating, gravure coating, blade coating, or roll coating. Is performed by c) step is carried out by impregnation with precursor solution and oxidative heat treatment, d) step is carried out by spin coating, and e) step is performed by chemical or physical vapor deposition (CVD or PVD). The method of claim 11, The semiconductor particle of step a) is TiO ₂ , the photosensitive nanoparticle of step b) is PbS, the metal precursor of step c) is a Ti precursor, The hole conducting organic material of step d) is 2,2 ', 7,7'-tetrakis- (N, N-di- p methoxyphenyl-amine) -9,9'-spirofluorene (spiro-OMeTAD; 2 , 2 ', 7,7'-tetrakis- ( N, N-di- p methoxyphenyl-amine) method for producing a near-infrared sensing device, characterized in that -9,9'-spirofluorene). The method of claim 15, The manufacturing method after step a) And forming a linker having a hydrophilic terminal and a thiol group in the porous semiconductor layer.

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