JP2001516150A - Organic diodes with switchable photosensitivity - Google Patents

Abstract

(57) Abstract: A switchable photosensitive organic diode detector (10) comprises an organic photo layer (12) of a photodiode and a detector circuit (15, 16) for applying a reverse or forward bias voltage to the diode. ). These diodes can be arranged in a matrix that functions as a high performance two-dimensional image sensor. These image sensors can achieve full color or selected color detection capability.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to organic photodiodes and the use of organic diodes in two-dimensional image sensors. In a more preferred embodiment, the present invention is directed to a voltage switchable organic photodiode that can be arranged as an image sensor in the form of a column-row (xy) passively addressable matrix. Regarding diodes. Here, an xy addressable organic image sensor (image array)
It has full color or selected color detection capability.

BACKGROUND OF THE INVENTION The development of image array photodetectors has a relatively long history in the device industry. Early approaches to imaging technology included devices based on thermal effects in solid materials. Following these were sensitive image arrays and matrices based on photodiodes and charge-coupled devices ("CCDs") made using inorganic semiconductors.

[0003] Photodiodes fabricated using inorganic semiconductors such as silicon represent a class of high quantum yield photosensitive devices. These photodiodes have been
It has been widely used in visible light detection applications. However, these photodiodes characteristically provide a flat photocurrent-voltage response, which makes them highly pixel-density xy matrix-addressable. It is difficult to use for manufacturing passive image sensors.
An "xy" matrix is a two-dimensional array in which a first set of electrodes is perpendicular to a second set of electrodes. When passive devices, such as resistors, diodes, or liquid crystal cells, are used as pixel elements at intersections, the matrix is often (as opposed to an "active" matrix, which controls the turn-on of each pixel using an active device, such as a thin film transistor). T) called a "passive" matrix.

In order to effectively address each pixel from the column and row electrodes in a passive matrix, pixel elements must have strong non-linear current-voltage (“I-
V ") characteristics or IV dependence with threshold voltage. This requirement provides the basis for constructing an xy-addressable passive display using light emitting diodes or liquid crystal cells. However, photodiodes fabricated using inorganic semiconductor crystals are impractical for use in high pixel density passive image sensors because the light response of the inorganic photodiode is reverse biased and not voltage dependent. Excessive crosstalk occurs between them. In order to avoid crosstalk, existing two-dimensional photodiode arrays made using inorganic photodiodes have to be manufactured by wiring each pixel individually, which is a difficult and costly procedure. For such individual connections, the number of input / output leads is proportional to the number of pixels. Therefore, the number of pixels in a commercial two-dimensional photodiode array is 16 × 16 =
It is limited to 256 or less. Typical commercial photodiode arrays include Si
emens KOM2108 5 × 5 photodiode array and Hama
Matsu S3805 16 × 16 Si photodiode array.

The development of CCD has provided another approach to high pixel density two-dimensional image sensors. A CCD array is an integrated device. CCD arrays are different from xy addressable passive matrix arrays. The principle of operation of a CCD involves the serial transfer of charge from pixel to pixel. These inter-pixel movements occur repeatedly, so that the charges eventually move to the edges of the array and are read. These devices use very large integrated circuit ("SLIC") technology and require a very high level of integrity during device fabrication. Therefore, (in the case of the 0.75 "to 1" size ^{CCD, ~ $ 10 3 ~ $} 10 4) high cost of the CCD array limits the commercial CCD product Sabuinchi dimensions.

[0006] Thin film transistor ("TFT") technology on glass or quartz substrates, originally developed for the needs of liquid crystal displays, is an active matrix substrate for manufacturing large xy-addressable image sensors. Can be provided. Large full-color image sensors fabricated using amorphous silicon (a-Si) pin photoelectric cells on a-Si TFT panels have recently been demonstrated [R.
A. Street, J.M. Wu, R.A. Weisfield, S.M. E. FIG. Nelson
And P. Nylen, Spring Meeting of Materialia
ls Research Society, San Francisco, Ap
ril 17-21 (1995); Yorkston et al., Mat. Res.
Soc. Sym. Proc. 116, 258 (1992); A. Street
t, Bulletin of Materials Research Soc
iety 11 (17), 20 (1992); E. FIG. Antonuk and R
. A. Street, US Pat. No. 5,262,649 (1993); A.
Street, U.S. Patent No. 5,164,809 (1992)]. Regardless, following the development of CMOS technology with sub-micron resolution, parallel efforts for small active pixel photosensors based on CMOS technology on silicon wafers have been renewed. For review, Eric
J. Lerner, Laser Focus World 32 (12) 54
, 1996]. This CMOS technology can realize a monochip image camera because it allows the photocells to be integrated with the driver and timing circuit.

[0007] CCDs, a-Si TFTs, and active pixel CMOS image sensors
Represents existing / new technologies for solid state image sensors. However, the costly processes involved in the manufacture of these sophisticated devices greatly limit the application of these devices. In addition, the use of SLIC technology in the manufacturing process allows commercial CCs to be used.
D and active pixel CMOS sensors are limited to sub-inch device dimensions.

[0008] Photodiodes made with organic semiconductors represent a new class of photosensors with promising process advantages. In the 1980's, there were early reports of fabricating photodiodes using organic molecules and conjugated polymers, but relatively small photoresponses were observed [for early studies of organic photodiodes,
G. FIG. A. Chamberlain, Solar Cells 8, 47 (198
See 3)]. In the 1990's there was an advance in using conjugated polymers as active materials. See, for example, the following report on the photoresponse in poly (phenylenevinylene) PPV and its derivatives: Karg, W.C. Ri
ess, V. Dyakonov, M .; Schwoerer, Synth. Me
tals 54, 427 (1993); Antoniadis, B .; R. H
sieh, M .; A. Abkowitz, S .; A. Jenekhe, M .; Stol
ka, Synth. Metals 64, 265 (1994); Yu, C
. Zhang, A .; J. Heeger, Appl. Phys. Lett. 64
, 1540 (1994); N. Marks, J.M. J. M. Halls, D.M.
D. D. C. Bradley, R .; H. Field, A .; B. Holmes,
J. Phys. : Condens. Matter 6, 1379 (1994);
R. H. Friend, A.C. B. Homes, D.E. D. C. Bradley, R
. N. Marks, U.S. Pat. No. 5,523,555 (1996)]. Recent advances have demonstrated that photosensitivity in organic photodiodes can be enhanced under reverse bias. In the ITO / MEH-PPV / Ca thin film device, 1
At 0 V reverse bias (430 nm), a photosensitivity of ９０90 mA / watt has been observed, corresponding to a quantum efficiency of> 20% el / ph [G. Yu, C.I. Zha
ng and A. J. Heeger, Appl. Phys. Lett. 64, 15
40 (1994); J. Heeger and G.W. Yu, US Patent No. 5,50
4,323 (April 2, 1996)]. Photodiodes fabricated using poly (3-octylthiophene) have been observed to have a photosensitivity in excess of 0.3 A / Watt over most of the visible spectral range with a bias of -15 V [G.
Yu, H .; Pakbaz and A.M. J. Heeger, Appl. Phys. L
ett. 64, 3422 (1994)].

Photosensitivity in organic semiconductors can be enhanced by excited state charge transfer, for example, by imparting photosensitivity to the semiconductive polymer with an acceptor such as C ₆₀ or a derivative thereof [N. S. Sariciftci and A.M. J
. Heeger, U.S. Patent No. 5,331,183 (July 19, 1994);
N. S. Sariciftci and A.M. J. Heeger, US Patent No. 5,4
No. 54,880 (October 3, 1995); S. Sariciftci, L
. Smilowitz, A .; J. Heeger and F.S. Wudl, Science
ce 258, 1474 (1992); Smilowitz, N.M. S. Sa
riccitci, R.C. Wu, C.I. Gettinger, A .; J. Heeger
And F. Wudl, Phys. Rev .. B 47, 13835 (1993);
N. S. Sariciftci and A.M. J. Heeger, Intern. J
. Mod. Phys. B 8, 237 (1994)]. Photoinduced charge transfer prevents premature recombination and stabilizes charge separation, thereby increasing carrier quantum yield for subsequent collection [B. Krabel, C.I. H. Le
e, D. McBranch, D.M. Moses, N.M. S. Sariciftci and A.M. J. Heeger, Chem. Phys. Lett. 213, 389 (
1993); Krabel, D.M. McBranch, N.M. S. Saric
ifci, D.C. Moses and A.J. J. Heeger, Phys. Rev ..
B 50, 18543 (1994); H. Lee, G.A. Yu, D.A. Mose
s, K.S. Pakbaz, C.I. Zhang, N .; S. Sariciftci, A. et al.
J. Heeger and F.S. Wudl, Phys. Rev .. B. 48, 1542
5 (1993)]. By using the charge transfer blend as the photosensitive material of the photodiode, an external photosensitivity of 0.2 to 0.3 A / W and an external quantum yield of 50 to 80% el / ph at 430 nm at a low reverse bias voltage can be obtained. Has been achieved [G.
Yu, J .; Gao, J .; C. Hummelen, F.C. Wudl and A.M. J. H
eeger, Science 270, 1789 (1995); Yu and A.M. J. Heeger, J.M. Appl. Phys. 78, 4510 (1995)
J .; J. M. Halls, C.I. A. Walsh, N.M. C. Greenham,
E. FIG. A. Marseglia, R.A. H. Field, S.M. C. Moratti
And A. B. Holmes, Nature 376, 498 (1995)].
At the same wavelength, the photosensitivity of the UV enhanced silicon photodiode is ０．２0.2 A / Watt regardless of the bias voltage [S. M. Sze, P
physics of Semiconductor Devices (Wile
y, New York, 1981) Part 5]. Thus, the photosensitivity of thin film photodiodes made using polymer charge transfer blends is comparable to that of photodiodes made using inorganic semiconducting crystals. These organic photodiodes, in addition to their high photosensitivity, show a large dynamic range,
In the range from 00mW / cm ² until nW / cm ^2, i.e., over the size of 8 orders, are relatively flat photosensitivity is reported [G. Yu, H .; Pakbaz and A.M. J. Heeger, Appl. Phys. Lett. 64, 3422 (1
994); Yu, J .; Gao, J .; C. Hummelen, F.C. Wudl and A.M. J. Heeger, Science 270, 1789 (1995);
G. FIG. Yu and A.M. J. Heeger, J.M. Appl. Phys. 78, 451
0 (1995)]. Polymer photodetectors can be operated at room temperature, and photosensitivity is relatively insensitive to operating temperature, with only a two factor reduction from room temperature to 80K [G. Yu, K .; Pakbaz and A.M. J. Heeger, App
l. Phys. Lett. 64, 3422 (1994)].

As in the case of the polymer light emitting device [G. Gustafsson, Y .; Cao,
G. FIG. M. Treacy, F.C. Klavetter, N.M. Colaneri and A.M. J. Heeger, Nature 357, 477 (1992); J.
Heeger and J.W. Long, Optics & Photonics N
ews, Aug. 1996, p. 24], high-sensitivity polymer photodetectors can be manufactured in large areas by processing from solution at room temperature or in unusual shapes (eg, on hemispheres for coupling with optical components or systems). ) Can be made or can be made in a flexible or foldable form. The advantages of the above process also allow the optical sensor to be manufactured directly on optical fiber. Similarly, organic photodiodes can be hybridized with electronic or optical devices, such as integrated circuits on silicon wafers. These unique features make organic photodiodes special for many new applications.

SUMMARY OF THE INVENTION The present applicant has now found a new application for increasing the photosensitivity of an organic photodiode by applying a reverse bias.

The Applicant has now found that this variable photosensitivity allows for an on-off voltage switchable photosensor. With reverse bias, typically greater than 1 V, and more typically in the range of 2 to 15 V, the photodiode is exposed to a sensitivity of 1 mA / W or more, specifically 10-500 mA / W, or 30-500 mA / W. It can be switched on with a sensitivity of 300 mA / W. The photosensitivity at voltages near the internal (built-in) potential is several orders of magnitude lower and is equivalent to zero at the output of an 8-16 bit digital readout circuit. Therefore, this state close to zero can be defined as the off state of the photodiode.

[0013] These voltage switchable organic photodiodes can serve as individual pixels in a passive diode array. These arrays may be in the form of an xy addressable array in which the anodes are connected via row (column) electrodes and the cathodes are connected via column (row) electrodes. All pixels can be selected, and information (intensity of incident light) of each pixel can be read out without crosstalk.

[0014] These arrays can take advantage of the processing advantages associated with fabricating organic diode structures from soluble semiconductive conjugated polymers (and / or precursor polymers thereof). Layers of these materials can be cast from solution, making it possible to produce large active areas on substrates having the desired shape. This also allows the active area to be made flexible. These photoactive materials can be patterned on optically uniform substrates by photolithography, microcontact printing, shadow masking, and the like. For light sensors for visible light sensing applications, the substrate may be opaque at λ <400 nm so that the pixels are insensitive to UV radiation.

[0015] The photoactive layers used in these switchable photodiodes are composed of organic materials. These organic materials take many forms. These organic materials may be conjugated semiconductive polymers and blends of polymers containing such materials. Donor-acceptor blends having a conjugated polymer that acts as a donor and a polymer and monomer acceptor can also be used, as well as molecular donors and acceptors (ie, molecules rather than macromolecules) well known in the art. Good. Examples of the latter include anthracene and its derivatives, pinacyanol and its derivatives, thiophene oligomers (such as sexithiophene 6T and octylthiophene 8T) and derivatives thereof, and phenyl oligomers (sexiphenyl or octylphenyl). In addition, multiple layers of organic semiconductive material may be used in a donor / acceptor heterojunction configuration. further,
Multiple layers of organic semiconductive material may be used in a donor / acceptor heterojunction configuration.

The organic image sensor enabled by the present invention may have mono-color or multi-color detection capabilities. In these image sensors, color selection can be achieved by combining an appropriate color filter panel with the organic image sensors and image sensor arrays already described. If desired, the color filter panel may serve as a substrate on which the image sensor is held.

Further, embodiments of the present invention provide an organic image sensor having full color detection capability. In these organic image sensors, the filter panel is composed of red, green and blue color filters that are patterned into a format corresponding to the format of the photodiode array. The panel of patterned filters and the patterned photodiode array are combined (and tuned) to form a color image sensor. The patterned color filter panel may be used as it is as a substrate of an image sensor.

[0018] Full-color detectability also indicates that 500 nm, 6 nm,
Achieved when red, green and blue are detected by three photodiodes with spectral response cutoffs of 00 nm and 700 nm, respectively. A red (600-700 nm) signal and a green (500-600 n) signal are obtained by differential operation in the readout circuit.
m) and blue (400-500 nm) signals are extracted.

These organic photodiodes, in addition to being used in their inherent response spectral range (typically between 200 nm and 1000 nm), also have ultraviolet (UV)
, X-rays, and other spectral ranges, such as the infrared (IR) spectrum. Exposure of photon energy outside the natural spectral range can be achieved by energy down or up conversion techniques. For example, exposure in the UV and X-ray spectrum
This can be achieved with a phosphor or scintillation layer located between the source and the light sensor. This layer converts the high energy radiation into visible luminescence that is detected by an organic light sensor. IR radiation and high energy particle radiation can be detected according to similar principles.

These organic light sensors are also inherently sensitive to radiation at certain wavelengths in the deep ultraviolet and X-ray spectral ranges. These wavelengths and the corresponding photon energies are determined from the inner core level (energy band) to the lowest unoccupied molecular orbital (LUMO).
) Or the optical transition to the bottom of the conduction band.

(Description of the Preferred Embodiment) The present invention will be further described with reference to the drawings.

The present invention provides a high-sensitivity photodiode having voltage-switchable photosensitivity. Photosensitivity can be switched on and off by applying a selected voltage, thereby reducing crosstalk between pixels in an array of such voltage-switchable photodiodes to an acceptable level. These switchable light sensors allow for the manufacture of two-dimensional (2D) passive image sensors with column-row (xy) addressability. Voltage switchable photodetectors are constructed in a metal-semiconductor-metal (MSM) thin film structure, and organic films, such as semiconductive polymer or polymer blend films, are used as the photoactive material. Detection of a selected color or multi-color in the visible or near ultraviolet can be achieved by coupling the image sensor to optical filter (s). The manufacturing process of red, green and blue (R, G, B) and full color image sensors uses an xy addressable polymer diode matrix with RGB (
Red, green, blue) by combining with a color filter panel or 500nm
, 600 nm and 700 nm, respectively, are fabricated by fabricating photodiodes on optically uniform substrates.

The visible or solar blind UV detection has an optical gap> 3.1
This can be achieved by using a photoactive material with eV (wavelength <400 nm) or by combining an organic light sensor with a smaller energy gap with a UV bandpass optical filter that is opaque in the visible. . In addition to exposure in the visible and UV ranges (200-400 nm), exposure in other spectral ranges, such as deep ultraviolet, X-ray, and IR, combines organic light sensors with a phosphor or scintillation layer. Can be achieved. High energy or IR radiation can be converted to visible radiation, which can then be detected by an organic photodetector. Radiation at certain wavelengths in the deep ultraviolet and X-ray spectral range can also be detected directly with these organic photodiodes. These wavelengths correspond to optical transitions from the inner core level (energy band) to the lowest unoccupied molecular orbital (LUMO) or bottom of the conduction band.

A voltage switchable photodiode enables a 2D image sensor. By using such a photodiode as a sensing element in a column-row matrix, an xy-addressable 2D passive image sensor that operates without crosstalk can be constructed. Since the photosensitivity shows strong voltage dependence, 2
The columns of pixels of the D photodiode matrix can be selected and turned on with appropriate voltage bias, leaving the remaining pixels in the other rows insensitive to incident light. Using this type of operation, a physical M-row, N-column 2D matrix is reduced to N separate linear diode arrays with M elements each. These isolated linear diode arrays have no crosstalk due to finite resistance between different columns of devices. With such a 2D passive photodiode array, an image can be read using a pulse train that scans each column of the matrix. In an xy addressable matrix, the number of contact electrodes is reduced to N + M compared to N × M for individual connections, making a large, high pixel density 2D image array practical. (Comparable to a high pixel density display array made using LCD technology). For example, 1000 ×
For a 1000 pixel array, the present invention reduces the number of electrodes required by a factor of 500. Thus, polymer image sensor matrices provide a unique approach to fabricating large, low cost, high pixel density 2D image sensing arrays using room temperature or low temperature manufacturing processes.

As demonstrated in the examples provided herein, the spectral response of a polymer image sensor can cover the entire visible spectrum with a relatively flat response. Portions of the visible spectrum can also be selected using bandpass or lowpass optical filters. Multicolor detection in the visible and near ultraviolet can be achieved by combining an image sensor with a color filter panel. The manufacturing process of a full color image sensor is described using an xy addressable polymer diode matrix and an RGB (red, green, blue) color filter panel.

Definitions and Device Structure In this description of the preferred embodiments and in the claims, reference will be made to a number of defined terms. One group of terms relates to the structure of a voltage switchable photodiode. A cross-sectional view of a voltage switchable photodiode is shown in FIG. The voltage switchable photodiode 10 is a metal-semiconductor-metal (M
-SM) It is configured using a thin film device configuration. Specifically, the device 10 may comprise an organic semiconductive material (s), such as a conjugated polymer, polymer blend, polymer / molecular polyblend, molecular blend or layer of organic molecules, or a multi-layer combination of the above materials. The structure consists of a “photo layer” (layer 12), and two “contact electrodes” (layers 11, 1) that serve as anodes and cathodes of photodiodes and extract electrons and holes from the photoactive layer, respectively.
3). One of the electrodes (layer 11 of FIG. 1) is transparent or translucent, allowing incident light 18 to be absorbed by the active layer (12).

An “anode” electrode is defined as a conductive material that has a higher work function than a “cathode” material.

With respect to the relationship between the electrodes 11 and 13, the active layer 12 and the light source 18 (or 18 ′), the same relationship is shown in FIGS. 1, 2, 3, 4 and 5, respectively. , 20, 30, 40 and 50.

As shown in FIGS. 1 and 2, electrodes 11 and 13 are respectively connected to line 1
It is connected to the bias voltage source 15 via 7 and 17 '. Detector 16 is wired in series with this circuit and measures the optical response generated by the photodiode in response to light 18. The same circuit is used for all the devices (10, 2) shown in FIGS.
0, 30, 40 and 50).

These devices may also include an optional substrate or support 14 as shown in FIGS. This is a solid, rigid or flexible layer designed to provide robustness to the diode and / or matrix array of diodes. When light is incident from the substrate side, the substrate should be transparent or translucent. Glass, polymer sheets, or flexible plastic films are commonly used substrates. For some applications, a broadband semiconductor wafer (SiC, SiN, etc.) that is transparent below the optical gap may be used.
In these cases, the lightly doped region may also serve as contact electrode 11.

A device having the inverse geometry shown in FIG. 2 is also useful in applications. In this configuration, light 18 is incident from the "back" electrode side, and an optically opaque material can be used as the substrate material. For example, by using an inorganic semiconductor wafer (such as silicon) as the substrate 14 and doping the semiconductor to a “conductive” level (defined below), the wafer can serve as both the substrate 14 and the contact electrode 11. Can be fulfilled. This inverted structure offers the advantage of integrating the photosensor (using integrated circuit technology) with a drive / readout circuit formed directly on the inorganic semiconductor substrate.

The incident light 18 (or 18 ′) generally has a wavelength in the visible part (400-700 nm).
), Ultraviolet wavelengths (100-400 nm), and infrared wavelengths (700-20
00 nm). As indicated, other wavelengths may be used where appropriate.

Some layers are designated as “transparent” or “translucent”. These terms are
Used to refer to the property of a material to transmit a substantial portion of the incident light incident on the material. The term "transparent" is used to indicate a substrate having a transmission of more than 50%, and the term "translucent" is used to indicate a substrate having a transmission between 50% and 5%. Is done.

A “conductive” layer or material typically has a conductivity greater than 0.1 S / cm. Semiconductive materials have a conductivity of 10 ^-14 to 10 ^-1 S / cm.

“Positive” (or “negative”) bias refers to when a higher potential is applied to the anode electrode (cathode electrode). When referring to a negative voltage value, as in the case of a reverse bias voltage applied to obtain high photosensitivity, a relative value is indicated with respect to an absolute value. That is, for example, a -10V (reverse) bias is greater than a -5V (reverse) bias.

The structure of an xy addressable passive photodiode matrix (2D image sensor 30) is shown in FIG. FIG. 4 shows the structure of a full-color image sensor 40 fabricated using an xy addressable photodiode array. In these devices, the anode and cathode electrodes 11 ', 13' are typically patterned in rows and columns perpendicular to each other. In certain applications, patterning of the photoactive layer 12 is not required. Each intersection of the row and column electrodes defines a photosensitive element (pixel) having a device structure similar to that shown in FIG. 1 or FIG. The width of the row and column electrodes 11 ', 13' defines the active area of each pixel.

A matrix of color filters 19 (each pixel of the color filters comprises a red, green and blue color filter 19 ′) is coupled to a photodiode panel. A separate color filter sheet similar to the color filter sheet used for color LCD displays [for review, see Tani and T.S. Sugiu
ra, Proceeding of SID, Orlando, Florida
(1994)] may be used for this purpose. In a more preferred embodiment, the color filter panel may be coated directly on the photodiode matrix substrate. The transparent electrode 11 (for example, indium-tin-
(Consisting of oxide ITO) may be manufactured over the color filter coating. With this configuration, high pixel densities with micron sized feature sizes can be achieved.

[0038] Full color detection can be achieved using another approach 50 as shown in FIG. In this approach, each full color pixel 12 'is 700
, 600 and 500 nm, respectively, having three long-wave cutoffs. These photodiodes consist of three photosensitive materials in a defined area on the substrate. The patterning of the active layer can be achieved by photolithography, screen printing, shadow masking, and the like. As demonstrated in embodiments of the present invention, the correct color information for red, green and blue can be obtained by differentiating the signals (at the readout circuit) from the three sub-pixels 12R, 12G and 12B. Optically uniform materials are used as substrates that are transparent in the visible and opaque in the UV.

(Photoactive Layer) The photoactive layer 12 of the voltage switchable photodiode is made of a thin organic semiconductive material sheet. The active layer may include one or more semiconductive conjugated polymers alone, or may include non-conjugated materials, one or more organic molecules, or combinations with oligomers. The active layer may be a blend of two or more conjugated polymers having similar or different electron affinities and different electron energy gaps.
The active layer may be a blend of two or more organic molecules having similar or different electron affinities and different electron energy gaps. The active layer may be a blend of conjugated polymers and organic molecules having similar or different electron affinities and different electron energy gaps. The latter offers a particular advantage in that different electron affinities of the components can lead to photoinduced charge transfer and charge separation, a phenomenon that enhances photosensitivity [N. S. Sariciftci and A.M. J. Heeger, U.S. Pat. No. 5,333,183 (July 1, 1994)
9); S. Sariciftci and A.M. J. Heeger, U.S. Patent No. 5,454,880 (October 3, 1995); S. Saricift
ci, L .; Smilowitz, A .; J. Heeger and F.S. Wudl, S
science 258, 1474 (1992); Smilowitz, N.M.
S. Sariciftci, R.A. Wu, C.I. Gettinger, A .; J. He
eger and F.E. Wudl, Phys. Rev .. B 47, 13835 (19
93); S. Sariciftci and A.M. J. Heeger, Inte
rn. J. Mod. Phys. B 8, 237 (1994)]. The active layer also
A series of heterojunctions using layers of organic materials or blends as described above may be used.

Thin films of organic molecules, oligomers, and molecular blends can be prepared by thermal evaporation, chemical vapor deposition (C
VD). Where thin films of conjugated polymers, polymer / polymer blends, polymer / oligomer and polymer / molecular blends can be manufactured by casting directly from a solution in a common solvent or using similar fluid phase processing. There are many. If a polymer or polyblend is used as the active layer, the device may be fabricated on a flexible substrate that creates an inherently mechanically flexible optical sensor.

Examples of typical semiconductive conjugated polymers include polyacetylene (“PA”) and its derivatives, polyisothianaphene and its derivatives, polythiophene (“P
T ") and its derivatives, polypyrrole (" PPr ") and its derivatives, poly (2,5-thienylenevinylene) (" PTV ") and its derivatives, poly (p-
Phenylene) (“PPP”) and its derivatives, polyfluorene (“PF”) and its derivatives, poly (phenylenevinylene) (“PPV”) and its derivatives, polycarbazole and its derivatives, poly (1,6-heptadiyne), But not limited to polyquinolene, and semiconductive polyaniline (ie, leuco emerald and / or emerald base form). Representative polyaniline materials are described in U.S. Patent No. 5,196,144. The above US patents are incorporated herein by reference. Of these materials, those that are soluble in organic solvents are preferred due to the advantages of processing those materials.

Examples of PPV derivatives soluble in common organic solvents include poly (2-methoxy-5)
-(2'-ethyl-hexyloxy) -1,4-phenylenevinylene) ("ME
H-PPV ") [F. Wudl, P .; -M. Allemand, G .; Srdan
ov, Z .; Ni and D.S. McBranch, Materials for N
online Optics: Chemical Perspectiv
es, S.S. R. Marder, J.M. E. FIG. Sohn and G.S. D. Stucky (The American Chemical Society, Washi)
ngton DC, 1991), p. 683], poly (2-butyl-5- (2-
Ethyl-hexyl) -1,4-phenylenevinylene ("BuEH-PPV")
[M. A. Andersson, G .; Yu, A .; J. Heeger, Synth
. Metals 85, 1275 (1997)], poly (2,5-bis (cholestanoxy) -1,4-phenylenevinylene) ("BCHA-PPV") [see U.S. Patent Application No. 07 / 800,555. In the present specification, the above patent application is incorporated by reference. ],and so on. An example of a soluble PT is poly (3-alkylthiophene) ("P3AT"), wherein the alkyl side chain contains more than 4 carbons, such as 5-30 carbons.

Organic image sensors can be manufactured using a donor / acceptor polyblend as the photoactive layer. These polyblends may be semiconductive polymer / polymer blends, or may be blends of suitable organic molecules and semiconductive polymers. Examples of donors of the donor / acceptor polyblend include, but are not limited to, the conjugated polymers just described, namely, PPV, PT, PTV, and poly (phenylene), and their soluble derivatives. Examples of acceptors of the donor / acceptor polyblend include poly (cyanophenylenevinylene (cy)
anaphenylenevinylene)) (“CN-PPV”) and its derivatives, fullerene molecules such as C ₆₀ and its functional derivatives (functi)
online, as well as, but not limited to, organic molecules previously used in the field of photoreceptors.

The photoactive layer may be formed using two semiconductive organic layers in a donor / acceptor heterojunction structure. In these structures, the donor layer is typically a conjugated polymer layer and the acceptor layer is a poly (cyanophenylene vinylene) ("CN-
PPV "), fullerene molecules such as C _60, as well as, PCBM and PCBCR
Or functional derivatives thereof, or organic molecules previously used in the field of photoreceptors. Examples of the heterojunction layer structure of the photoactive _{layer, PPV / C 60, MEH-} PPV / C 60, PT / C 60, P3AT / C 60, MEH
And the like -PPV / C _60, but is not limited thereto.

The active layer also consists of a broadband polymer, such as poly-N-vinylcarbazole (“PVK”), doped with dye molecule (s) to enhance photosensitivity in the visible spectral range. You may. In these cases, the broadband organics are
It acts as both a host binder and a hole (or electron) transport material. Examples include, but are not limited to, PVK / o-chloranil, PVK / rhodamine B, and PVK / coronene.

The photoactive layer may use organic molecules, oligomers, or molecular blends as the photoactive layer. In this embodiment, the photosensitive material is chemical vapor deposition, molecular epitaxy,
Alternatively, it can be manufactured into a thin film by other known film deposition techniques. Examples of suitable materials include anthracene, phthalocyanine, 6-thiophene ("6T"
), Triphenylene and its derivatives such as 2,3,6,7,10,11-hexahexylthiotriphenylene, or molecular blends such as 6T / C ₆₀ , 6T / pinacyanol, phthalocyanine / o-chloranil. However, the present invention is not limited to these. The photoactive layer may also have a multilayer structure combining the above materials.

Examples of organic molecules, oligomers and molecular blends that can be used in the active layer include:
Anthracene and its derivatives, tetracene and its derivatives, phthalocyanine and its derivatives, pinacyanol and its derivatives, fullerene (“C ₆₀ ”)
And its derivatives, such as thiophene oligomers (sixetiophen “6T” and octithiophene “8T”) and their derivatives, phenyl oligomers (sixephenyl or octiphenyl and the like) and their derivatives, such as 6T
/ C ₆₀ , 6T / pinacyanol, phthalocyanine / o-chloranil, anthracene / C ₆₀ , and anthracene / o-chloranil.

In some embodiments, active layer 12 includes one or more organic additives (optically inactive) to modify and enhance device performance. Examples of additive molecules include anionic surfactants such as ether sulfates having a common structure.

[0049] _{R (OCH 2 CH 2) n} OSO 3 - M + wherein, R represents an alkyl alkylaryl, M ⁺ represents a proton, metal or ammonium counterion, n is represents the moles of ethylene oxide , Typically n = 2-40.

Providing such an anionic surfactant as an additive to improve the performance of polymer light emitting diodes is disclosed in Y. Cao [US Patent Application Serial No. 08 / 888,316. In the present specification, the above patent application is incorporated by reference. ].

[0051] Other types of additives include solid electrolytes or organic salts. Examples include poly (ethylene oxide), lithium trifluoromethanesulfonate, or blends thereof, tetrabutylammonium dodecylbenzenesulfonate, and the like. The application of such electrolytes to luminescent polymers and the invention of new types of light emitting devices is described in Q.A. Pei and F.S. Klav
[US Patent Application Serial No. 08/268,
No. 763].

When the active layer consists of an organic blend having two or more phases with different electron affinities and optical energy gaps, usually nanoscale phase separation occurs and a heterojunction is formed in the interface region. The phase (s) with higher electron affinity acts as electron acceptor (s), and the phase with lower electron affinity (or lower ionization energy) as electron donor (s) These organic blends constitute a class of charge transfer materials and enable a photo-initiated charge separation process defined by the following steps [NS Sariciftci and AJ Heeger.
, Intern. J. Mod. Phys. B 8, 237 (1994)].

[0053]

(Equation 1)

Here, (D) shows an organic donor, (A) shows an organic acceptor,
3 represents a singlet or triplet excited state, respectively.

The typical thickness of the active layer is in the range of hundreds of Angstroms to thousands of Angstroms, ie, 300-5000 ° (1 Angstroms = 1 = 1).
^0-8 cm). Although active film thickness is not critical, device performance can typically be improved by using thinner films having an optical density of 2 or less in the spectral range of interest.

(Electrode) As shown in FIG. 1 and FIG. 2, the organic photodiode of the present invention
Configured in a -M configuration, the organic photoactive layer is coupled on two sides to a conductive contact electrode. In the configuration shown in FIG. 1, the transparent substrate 14 and the transparent electrode 11
Used as one contact electrode. Indium-tin-oxide ("ITO
)) May be used as the electrode 11. Other transparent electrode materials include aluminum-doped zinc oxide ("AZO"), aluminum-doped tin oxide ("ATO"), tin oxide, and the like. These conductive coatings consist of doped metal oxide compounds that are transparent from the near ultraviolet to the mid-infrared.

The electrode 11 of FIG. 1 (or 13 of FIG. 2) is disclosed in US Pat. No. 5,232,631 and Appl. Phys. Lett. 60, 2711 (1992). The polyaniline film serving as an electrode can be cast from a solution having high uniformity at room temperature. Organic conductive electrodes, in combination with a polymer substrate and an organic active layer, allow these optical sensors to be manufactured in a completely flexible manner. Transparent or translucent electrode (11 in FIG. 1 or 13 in FIG. 2)
Other conductive polymers that can be used for polyethylene dioxythiophene polystyrene sulfonate (“PEDT / PSS”) [Y. Cao, G .; Yu,
C. Zhang, R.A. Menon and A.M. J. Heeger, Synth. M
et al., 87, 171 (1997)], dodecylbenzenesulfonic acid ("D
BSA ") doped poly (pyrrole) [J. Gao, A .; J. Heege
r. Y. Lee and C.I. Y. Kim, Synth. Metals 82,
221 (1996)].

A thin translucent layer of a metal (Au, Ag, Al, In, etc.) may be used as the electrode 11 in FIG. 1 and 13 in FIG. A typical thickness of this translucent metal electrode is 50
The light transmittance is between 80% and 10%. Suitable dielectric coatings (often in the form of multilayer dielectric stacks) can increase the transparency in the spectral range of interest [see, for example, S.M. M. Sze, Phy
sics of Semiconductor Devices (John W
iley & Sons, New York, 1981) Chapter 13
].

The “back” electrode 13 of FIG. 1 (and 11 of FIG. 2) typically comprises Ca, Sm,
It is made of a metal such as Y, Mg, Al, In, Cu, Ag, and Au. A metal alloy may be used as an electrode material. These metal electrodes can be manufactured, for example, by thermal evaporation, electron beam evaporation, sputtering, chemical vapor deposition, melting processes, or other techniques. The thickness of electrode 13 in FIG. 1 (and 11 in FIG. 2) is not critical, and may be hundreds of Angstroms to hundreds of microns or more. The thickness can be controlled to achieve a desired surface conductivity.

For example, if desired for a photodiode having detectability on both the front and back sides, the above transparent and translucent materials may be used as the “back” electrode 13 of FIG. 1 (and 11 of FIG. 2). Is also good.

The patterning of the row and column electrodes shown in FIGS. 3 and 4 is achieved by standard patterning techniques well known in the semiconductor industry, such as shadow masking, photolithography, silk screen printing, or stamping (microcontact) printing can do. These methods are well known to those skilled in the display art.

Color Filter Coating Some applications are directed to multi-color detection or detection of selected colors. These can be achieved by combining the light sensor with a color filter coating and by appropriately selecting the material of the photoactive layer.

One type of application is selected spectral response, eg, 500-600
nm. One effective approach is to choose an organic photodiode (e.g., a photodiode made using MEH-PPV) with a low energy cutoff of 600 nm, and use a long wavelength pass optical filter (
(With a cutoff of 500 nm). The spectral response of semiconductive oligomers and polymers can be controlled by altering the side chain or backbone structure. For example, by changing the side chain of the PPV system, the optical gap can be adjusted from 500 nm to 700 nm. Another approach to achieving bandpass selection is to place a bandpass optical filter in front of an organic photodiode with a wider spectral response.

In many applications of optical imaging, full-color detection is the target. This allows the sensor elements (pixels) to be red (600-700 nm), green (50 nm) similar to the response typically used in liquid crystal display (LCD) color display technology.
0-600 nm) and blue (400-500 nm) (R, G, B) can be achieved by dividing into three sub-pixels, each having a response to the spectral region (shown in FIG. 4).

A simple but effective approach to a full color image sensor is shown in FIG. In this approach, the photodiode matrix consists of one sheet of unpatterned active layer. The active area is defined by row and column electrodes. The spectral response of these organic photodiodes is in the visible range (400 to
700 nm). Color selection is achieved by a color filter panel in front of the transparent electrodes. There are many organic materials or blends that have a light response that covers the entire visible spectrum. Examples are “P3OT”, poly (3-
PT derivatives such as (4-octylphenyl) thiophene [M. R. Ander
sson, D.S. Seelese, H .; Jarvinen, T.W. Hjertberg
, O. Inganas, O .; Wennerstrom and J.W. E. FIG. Oster
holm, Macromolecules 27, 6503 (1994)], P
TV and its derivatives.

Several color filter technologies have been developed and are widely used for color displays made using liquid crystal technologies such as dyeing, pigment dispersion, printing and electrodeposition [M. Tani and T.S. Sugiura, Digest of SID 9
4 (Orlando, Florida)]. Another approach uses a multilayer dielectric coating based on optical interference. Due to better stability, pigment dispersion has become the main process used for large scale manufacturing. Transparent electrode coating (I
Designed patterns of color filter panels (eg, TO) are an existing field and are commercially available in the display industry. The designed pattern is often a triangular, striped (similar to that shown in FIG. 4) or diagonal mosaic configuration. This type of substrate can be used in the manufacture of the full color image sensor shown in FIG.

The photodetectors provided by the present invention can be adapted to respond to various types of ionized particles in addition to the photons themselves. This can be achieved by incorporating a scintillation material adapted to emit photons in response to the ionized particles into the photodetector structure. This material may be present in the admixture with the active layer, as a separate layer, or as part of the substrate or transparent electrode. In one embodiment, the scintillation material is a phosphor present, for example, as a phosphor layer.

Examples of ionized particles that can be detected with the device of this structure include high energy photons, electrons, and X-rays, where the ionized particles are specific to X-rays and the beta and ionized particles are It is unique. Radiation at certain wavelengths in the deep ultraviolet and X-ray spectral range can also be detected directly with these organic photodiodes. These wavelengths correspond to optical transitions from the inner core level (energy band) to the lowest unoccupied molecular orbital (LUMO) or bottom of the conduction band.

Emission in the IR region for photon energies below the light absorption gap of the photoactive material (s) is due to the phosphor layer being able to convert low energy IR photons to higher energy visible photons. , In a similar manner.

Application of the Invention The invention of a voltage-switchable organic photodiode provides the basis for the manufacture of large, low-cost 2D image sensors based on an xy-addressable passive diode matrix. This type of photodiode exhibits high photosensitivity (typically in the range of 30-300 mA / W) at a given reverse bias, and exhibits substantially zero response at bias voltages near the built-in potential. Thus, the row of pixels in such a photodiode column-row matrix can be selected by setting the selected row to reverse bias and biasing the other row of pixels with a voltage near the built-in potential. . In this way, crosstalk from pixels in different rows is eliminated. The image information of the pixels in the selected row can be correctly read out in both the serial mode and the parallel mode. Information on the pixels in the other rows can be read out sequentially or in a selected manner by setting the subject row to reverse bias. The xy-addressable organic photodiode matrix can be made large, at low manufacturing cost, on a desired shape or flexible substrate, and hybridizable with other optical or electronic devices. A new type of 2D image sensor is provided.

In the case of a linear diode array, the anode (or cathode) of the diode is
It can be connected as a common electrode. The traditional expression is "common anode" or "common cathode".

In the case of a common anode, the common anode is connected to a constant voltage level (eg, zero volts) in the readout circuit. The cathode of each diode is Von (+
10 V) or Voff (-0.2 V or 0 V) is connected to the read circuit. When the cathode is biased at a positive voltage (higher potential level than the anode of the same diode), the diode is reverse biased.

In the case of a common cathode, the common cathode is connected to a constant voltage level (eg, zero volts) in the readout circuit. The anode of each diode is Von (-
10 V) or Voff (+0.2 V or 0 V) is connected to the reading circuit. If the anode is biased at a negative voltage (a lower potential level than the cathode of the same diode), the diode is in reverse bias.

Readout circuits are often connected by a common electrode at a constant potential level (eg, zero volts).

For a 2D matrix, when the column electrodes are scanned, the row electrodes are connected to a given voltage level (eg, 0V). The selected column is biased at Von and the rest are V
selected with off. The readout circuit is arranged on a row electrode (having a constant potential level such as 0 V). In this drive mechanism, no electrodes are disconnected from the drive circuit (ie, no electrodes are floating). Each diode in the selected column is connected one at a time so that the readout circuitry does not mix image signals from different pixels.
The diodes of the diodes that have received Von (only the column is selected) and are not selected remain at Voff. The anode electrode of each diode can be connected to either a row electrode or a column electrode.

Specific advantages of the present invention over the prior art include the following.

(I) A switchable photosensitive organic light sensor. With a selected reverse bias voltage, high photosensitivity can be switched on (typically 30-300 m
A / W range). Photosensitivity can be effectively switched off when the diode is externally biased at a voltage near the potential corresponding to the internal potential.

(Ii) An xy-addressable 2D passive image sensor manufactured using organic photodiodes with switchable photosensitivity. With appropriate electronic pulse sequences, crosstalk-free readout can be achieved with these passive image sensors.

(Iii) Multi-color detection and full-color image detection can be achieved by coupling the image matrix to a color filter panel or by manufacturing the image sensor matrix directly on the color filter panel.

(Iv) Organic photodetector arrays have other known advantages that characterize devices made with organic materials, such as soluble conjugated polymers (eg, large area, desired on rigid or flexible substrates). Easy to manufacture into a shape, processed at room temperature, easy to hybridize with optics, electro-optics, opto-electric or electrical devices)
Promises large, low cost, high pixel density 2D image sensors used in office automation, industrial automation, biomedical equipment, and consumer electronics.

Example 1 Example 1 A thin MEH-PPV film 12 spin-cast from a solution on an ITO / glass substrate 14
A voltage switchable photodiode was fabricated by depositing a 5000A calcium contact (13) in the table. Prior to that, the glass substrate was partially coated with a contact layer 11 of indium-tin-oxide (ITO). The active area of each device was 0.1 cm ² . MEH-PPV films were cast from a 0.5% (10 mg / 2 ml) xylene solution at room temperature. For details on the synthesis of MEH-PPV, see Reference [F. Wudl, P .; M. Allemand, G .; S
rdanov, Z .; Ni and D.S. McBranch, Materials f
or Nonlinear Optics: Chemical Perspe
actives, S.C. R. Marder, J.M. E. FIG. Sohn and G.S. D. Stu
cky (American Chemical Society, Washi)
ngton DC, 1991) p. 683]. The thickness of the active layer was adjusted by changing the concentration of the solution, changing the rotation speed of the spinner head, and applying multiple coating layers.

Electrical data was obtained using a Keithley 236 source-measuring unit. The excitation source was a tungsten-halogen lamp filtered with a bandpass filter (430 nm center wavelength, 100 nm bandwidth) and collimated to form a uniform illumination area of 5 mm x 10 mm. The maximum optical power at the sample was 20 mW / cm ^{2 as} measured by a calibrated power meter. A set of neutral density filters was used to measure intensity dependence.

FIG. 6 shows the magnitude of the photocurrent (absolute value) as a function of the bias voltage under illumination at 430 nm and 20 mW / cm ² . The photocurrent at a bias of 1.5V is ~ 3
× 10 ⁻⁸ A / cm ² , with a reverse bias of −10 V increased to 9 × 10 ⁻⁴ A / cm ² corresponding to a photosensitivity of 45 mA / W and a quantum efficiency of 13% el / ph. The photosensitivity at 1.5V bias was actually zero in the readout circuit because the photosensitivity ratio between the two bias voltages was 3 × 10 ⁴ . The degree of this difference has enabled analog-to-digital (A / D) converters with 8-12 bit resolution.

The optical response is measured over the entire measurement range of nW / cm ² to tens of mW / cm ^{2 by} the light intensity (
I ^0.92-1 ) and increased almost linearly. At 20 mW / cm ² (highest light intensity of the measurements) no sign of saturation was observed.

In these devices, Al, In, and C were applied to the opposite electrode 13 (see FIG. 1) as a cathode.
Other metals such as u and Ag were also used. In all of these devices, FIG.
The same photosensitivity as the photosensitivity shown in Table 2 was observed. The off-state voltage in proportion to the internal potential of the photodiode changed with the work function of the metal. The off-state voltage is determined by the work function difference between the metal cathode and the ITO anode. Table 1
Figure 3 shows the off-state voltage seen for a MEH-PPV photodiode with several metal electrodes.

This example demonstrates that high photosensitivity can be achieved with a MEH-PPV organic photodiode under reverse bias. The desired photosensitivity can be achieved with a predetermined reverse bias. Photosensitivity can be switched off with an appropriate bias voltage depending on the electrode material selected. As shown in Table 1, an air stable metal having a work function greater than 4 V can be used for the electrodes of the organic photodiode. This example also demonstrates the wide dynamic range of a polymer photodiode, that is, a dynamic range sufficient to allow image detection at multiple gray levels.

[0087]

[Table 1]

Example 2 The device of Example 1 was manufactured on a flexible ITO / PET substrate. The thickness of the PET sheet used as the substrate was 5-7 mil (150-200 mm).
Similar device performance was observed.

This example demonstrates that voltage-switchable organic photodiodes can be fabricated into thin structures, flexible shapes, or desired shapes to meet the specific requirements of a particular application.

Example 3 The device of Example 1 was manufactured on glass and PET substrates. In these devices, an organic conductive coating or ITO overcoated with a conductive organic film was used instead of the ITO anode 11. As an organic electrode, PANI-
CSA and PEDT / PSS were used. The PANI-CSA layer was spin cast from m-cresol solution [details on the preparation of the PANI solution and the PANI-CSA membrane are disclosed in US Pat. No. 5,232,631]. PEDT
-PSS membrane was prepared using the aqueous dispersion supplied by Bayer (1.3% W / W) [B
ayer prototype TP AI 4071]. For more information on composition,
Reference [G. Heywang and F.W. Jonas, Adv. Materials
4, 116 (1992)]. Then, cast film (cast)
The film was calcined at 50-85 ° C. for several hours in a vacuum oven or N ₂ dry box. In the case of PEDT / PSS, the film was finally baked at a temperature above 100 ° C. for a few minutes to complete the drying process. The thickness of the conductive polymer electrode was controlled from hundreds of angstroms to thousands of angstroms.

The light transmission spectrum of the polymer anode electrode, including data from PANI-CSA and PEDT-PSS, is shown in FIG. FIG. 7 also shows the spectral response V (λ) of a normal human eye. The data shows that these organic conductive electrodes can be used in optical sensors for applications in the visible spectral range. Furthermore, PEDT-
PSS electrodes can also be used in the ultraviolet (250-400 nm) and near infrared. Thus, polymer electrodes can be used in photosensors with full color (white or R, G, B) detection.

Devices were fabricated using ITO / PANI-CSA and ITO / PEDT-PSS bilayer electrodes in addition to electrodes made using only PANI-CSA or PEDT-PSS. In these cases, the polymer electrodes were cast in thin layers (thicknesses of hundreds of angstroms) to maximize light transmission. Organic light emitting devices with double layer electrodes have demonstrated improved device performance, such as carrier injection and device stability. Examples are provided in U.S. Patent Application Serial Nos. 08 / 205,519 and 08 / 609,113.

The photosensitivity of the device with the organic anode electrode or double layer electrode was similar to the photosensitivity shown in FIG. That is, it was several tens mA / W at a reverse bias voltage in the range of -5V to about -10V.

[0094] This example demonstrates that conductive polymer materials can be used as electrode materials for photodiodes and image sensors. These plastic electrode materials offer the opportunity to manufacture organic light sensors in a flexible or foldable form. This example also demonstrates that a polymer electrode can be inserted between the metal-oxide transparent electrode (such as ITO) and the active layer to modify interface properties and device performance.

Example 4 The apparatus of Example 1 was repeated. A thin buffer layer was inserted between the ITO layer and the MEH-PPV layer to reduce leakage current through pinhole defects in the active layer.
Materials used for the buffer layer are PAZ, TPD (prepared by chemical vapor deposition) and PVK (cast from cyclohexanone solution). The thickness of the buffer layer is
100-500 °. The light response of these devices was similar to the light response shown in FIG. However, in these devices, the magnitude of the dark current (often caused by microshorts due to pinholes in the active layer) was reduced. In these devices without short circuits, a photon flux as small as 10 nW / cm ² was detected under DC operation. In these devices, the off-state voltage was 1.6-1.7 V, slightly higher than the device of Example 1.

This example demonstrates that a buffer layer can be inserted between the active layer and the contact electrode (s) to reduce device shorts and improve device response to weak light. I do. This buffer layer may consist of organic molecules by chemical vapor deposition or may consist of a polymer material by a wet casting process.

Example 5 The apparatus of Example 1 was repeated. The active material MEH-PPV was blended with the anionic surfactant Li-CO436 in a molar ratio of 0, 1, 5, 10 and 20%. Li-CO436 was purchased from Phone-Poulenc Co. Synthesized by a displacement reaction from Alipal CO436 (ammonium salt nonylphenoxyether sulfate) supplied by Y. Cao, U.S. Patent Application Serial No. 08 / 888,316]. Al was used as the cathode. Blended L
In the device using i-CO436, the photosensitivity was enhanced. For example, MEH-PP
V: In an apparatus manufactured using Li-OC436 (10 wt%), Li-OC
The photocurrent was increased by a factor of two compared to a similar device made without 436. Further, the off-state voltage is changed from 1.1 V of the ITO / MEH-PPV / Al device (see Example 1) to ITO / MEH-PPV: Li-OC436 (20
%) / 1.5V of Al device. A similar effect is found in ITO / MEH-PPV
/ Li-OC436 / Al devices were also observed.

In this embodiment, an organic additive may be added to the active layer, or may be inserted between the active layer and the contact electrode, in order to modify device performance such as photosensitivity and off-state voltage. Demonstrate good things.

Example 6 A voltage-switchable photodiode was replaced with an ITO having the same structure as that shown in FIG.
/ MEH-PPV: PCBM / metal. PCBM (C₆₀Derivatives)
Serves as the acceptor of the donor-acceptor pair, and MEH-PPV
Played a role as a donor. The active area of these devices is ~ 0.1 cm ^Two Met. A blend solution was prepared by mixing 0.8% MEH-PPV and 2% PCBM / xylene solution in a 2: 1 weight ratio. This solution is clear
, And could be processed at room temperature. The solution is_TwoAfter storage in the box for more than 1.5 years, no aggregation or phase separation was observed. The active layer is
From 1000 to 2000 rpm. Typical film thicknesses are 1000-2
It was in the range of 000 °. Ca, Al, Ag, Cu and Au are transferred to the counter electrode 13
Used as In each case, the membrane was deposited at 1000-5000 ° by vacuum evaporation.
Was piled up.

FIG. 8 shows ITO / MEH-PPV: PCBCR / A in the dark and under light illumination.
1 shows the IV characteristics of the device. The thickness of the blend film was ~ 2000mm. The dark current saturated at １1 nA / cm ² at voltages below 3 V and then increased super-linearly at high bias voltages (> E _g / e). Zener tunneling can explain this effect. Photocurrent was measured. The photocurrent at 0.65 V is ~ 1 × 10 ^-7 A
/ Cm ² and increased to 5 × 10 ⁻⁴ A / cm ² at a bias of −10 V. ON-
The off ratio was ５5000. Devices with thinner blend films showed improved photosensitivity and higher on-off ratios. Similar photosensitivity was observed in devices fabricated with other metals as counter electrodes. These are Ag, Cu, Ca, Sm
And Pb.

[0102] The other organic molecules such as C _60, was used as a light acceptor. Other mixtures were prepared using the C ₆₀ derivative PCBM. Higher photosensitivity was observed from MEH-PPV: PCBM treated from 1,2-dichlorobenzene solution. Photosensitivity reached 0.2 A / W at 430 nm when biased at -2V.

[0102] This example, by molecular acceptor blended with the donor polymer such as C _60, demonstrates that further improved photosensitivity. High photosensitivity can be achieved at a relatively low bias and low field (~10 ⁵ V / cm). This example also demonstrates that photosensitivity can be switched to near zero when the device is biased with a voltage that balances the internal built-in potential (０．６0.65 V for an Al cathode). The data in this example show that due to the low dark current levels of polymer photodiodes, polymer photodiodes can be used to detect weak light up to intensity levels of tens of nW / cm ² . Thus, polymer photodiodes have a dynamic range ranging from nW / cm ² to 100 mW / cm ² over more than 6 orders of magnitude.

Example 7 An apparatus similar to the apparatus of Example 6 was manufactured using the same manufacturing process as that of Example 6 to 4.5 cm × 4 cm (18 cm ² ) and 3.8 cm × 6.4 cm ( It was manufactured using a 24.3 cm ² ) glass / ITO substrate and PET / ITO substrate. An IV characteristic similar to the IV characteristic shown in FIG. 8 was observed. A photodiode manufactured using a flexible PET substrate was bent in a circular shape without changing its photosensitivity.

This example demonstrates that a high-sensitivity, voltage-switchable optical sensor can be manufactured on a large scale. With a flexible PET substrate, the optical sensor can be bent into the desired shape for special requirements in the fields of optics, physics and biomedical.

Example 8 MEH-PPV: CN-PPV, ie 2 as donor and acceptor phases
A device similar to the device of Example 6 was repeated using an active layer consisting of a polyblend having two polymers. Ca and ITO were used as the cathode and anode electrodes, respectively. Although an IV characteristic similar to the IV characteristic shown in FIG. 8 was observed, the off-state voltage was １1. It changed to 2V.

Example 9 An apparatus similar to that of Example 6 was repeated using an active layer consisting of sexithiophene (6T): PCBCR, a blend having two organic molecules as donor and acceptor phases. Was. An IV characteristic similar to the IV characteristic shown in FIG. 8 was observed.

Examples 8 and 9 show that the active layer of the voltage switchable photodiode may be a blend of organic molecules in addition to the polymer / molecule blend as demonstrated in Example 6, It demonstrates that it may be a blend of conjugated polymers. The data of these examples, together with the data of Example 1, also demonstrate that for a given cathode, such as Ca, the off-state voltage varies with the electronic structure of the active material.

Example 10 Voltage switching using P3OT as an active layer having an ITO / P3OT / Au structure
A possible organic photodiode was produced. IV characteristics in the dark and under light illumination
Is shown in FIG. Because the work function of Au is higher than that of ITO,
Here, the Au electrode plays a role as an anode. Positive bias is the higher voltage
The position was defined to be assigned to the Au electrode. Light is the cathode (ITO) electrode
Incident. In this experiment, a 633 nm He-Ne laser was applied at 10 mW / cm. ^Two Used as an illumination source having a photon density of

The built-in potential of this photodiode was reduced to almost zero volt. Therefore, the off state of the photodiode was changed to a voltage close to zero volt. -12
Photocurrent in V is 1 mA / cm ^2, which was 1 0 ⁴ times the photocurrent at zero bias. In a similar device, a ratio I _ph (−12 V) of 1.5 × 10 ⁵ or more
/ I _ph (0) is realized. The photosensitivity at 633 nm is ２０20% ph /
１００100 mA / W corresponding to the quantum efficiency of el. The dark current in the test range was lower than 5 × 10 ⁻⁷ A / cm ² . The photocurrent / dark current ratio was greater than 1000 over a wide bias range (-4 to -12 V).

This example demonstrates that the proper choice of active and electrode materials can change the off state of a photodiode. This voltage can be set to a voltage close to zero volts. A photodiode matrix manufactured using this type of photodiode can be driven by a unipolar pulse train, which simplifies the drive circuit. A large on / off switching ratio and a large photocurrent / dark current ratio allow photodiodes to be used in the manufacture of xy addressable passive matrices with high pixel density and multiple gray levels. become.

Example 11 A two-dimensional photodiode matrix was manufactured in rows 7 and 40. The pixel size was 0.7 mm x 0.7 mm. The space between the row and column electrodes is
It was 1.27 mm (0.05 "). The total active area was ~ 2" x 0.35 ". Typical IV characteristics from a pixel are shown in Figure 10. White light from a fluorescent light in the ceiling of the house was used as an illumination source with an intensity of 数 several tens of μW / cm ² , which is much lower than the light intensity used in document scanners.

This example demonstrates that a pixelated photodiode matrix can be manufactured without shorts and crosstalk. This example also demonstrates that these devices can be used in applications having light intensities of 1 microwatt / cm ² or less. Thus, polymer photodiode matrices are practical for imaging applications under relatively weak light conditions.

Example 12 A scanning mechanism for a photodiode matrix was developed (see FIG. 11). Due to the strong voltage dependence of the photosensitivity, the columns of pixels of the 2D photodiode matrix can be selected with an appropriate voltage bias and turned on, leaving adjacent rows of pixels insensitive to incident light. it can. Under such operation, physical M rows,
The N-column 2D matrix is reduced to N separate M-element linear diode arrays with no cross-talk between columns. This reminds us of the concept used in solving 2D integrals with dimensionality reduction as follows.

[0114]

(Equation 2)

When such a 2D passive photodiode array is used, an image can be read with a pulse train that scans each column of the matrix.

FIG. 11 shows an instantaneous “snapshot” of the voltage distribution in a 7 × 40 photodiode matrix. At a particular time t, all pixels except column 1 were biased at + 0.7V. All pixels in row 1 were biased at -10V to achieve high photosensitivity (thousands of mA / watt). The information for each pixel in column 1 was read out in both a parallel (using N channel converters and A / D converters) or serial (using N channel analog switches) sequence. Pixels in the other columns were selected by sequentially switching the column bias from + 0.7V to -10V. A digital shift register was used for column selection.

In order to simplify the driver circuit, the optical sensor is set to 0 V and the reverse bias voltage (−2 to
It was preferred that it could be switched on and off between -10V). Such a unipolar voltage switchable photodiode was demonstrated in ITO / P3OT / Au, as shown in Example 10.

Example 13 A multi-gray level image was selected and the image was scanned with a 7 × 40 photodiode matrix according to the scanning mechanism described in Example 12. The first image and the readout image were photographed. The readout image reproduced the original image with excellent fidelity.

This example demonstrates that a voltage switchable photodiode can be used as a pixel element in a column-row matrix as shown in FIG. The photodiode of each pixel can be effectively addressed from the column and row electrodes. Image information having multiple gray levels can be read out without distortion.

Example 14 Devices similar to those of Example 10 were fabricated and the spectral response of these devices was measured at a reverse bias of -15V. The data is shown in FIG. Conventional inorganic photodiodes have significantly reduced sensitivity at shorter wavelengths, whereas P3OT photodiodes have a relatively flat response at wavelengths shorter than 630 nm. 350n
The clear decrease in sensitivity at wavelengths below m is mainly due to the transmission cutoff of the glass substrate coated with ITO. At -15 V bias, sensitivity at 540 nm is 0.35 A / W (up to 80% el / ph quantum yield).
Reached. This is the same value obtained with a UV-enhanced Si diode. 40
Similar photosensitivity values continued in the UV region below 0 nm.

This example demonstrates a highly photosensitive organic photodiode with a response that simultaneously covers the entire near ultraviolet and visible spectrum.

Example 15 A voltage switchable photodiode was manufactured to achieve a response similar to the visual response V (λ) of the human eye. These devices were manufactured by coating a long wavelength pass filter on the front panel of a glass substrate of a device similar to that shown in Example 15. The coating material in this example was a layer of PPV that changed from the precursor film at 230 ° C. The optical response of the filtered and unfiltered devices is shown in FIG. 13a. For comparison, the visual response V (λ) of the human eye (
FIG. 13b) and the transmittance of the PPV optical filter. Although the optical response of the P3OT diode closely matched V (λ) at wavelengths longer than 560 nm, the light transmission of the PPV filter followed V (λ) over a wide range between 450 nm and 550 nm. .

This example is a polymer photodetector having a visual response essentially equivalent to V (λ), a polymer photodetector of great importance in photonics and biophysics / biomedical applications. Demonstrate.

[0124] Example 16 polyblend MEH-PPV: using a C _60, to produce a solar blind UV detectors. ITO and Al were used as anode and cathode materials. These devices were purchased from Melles Griot Inc. UV purchased from
It was manufactured on a band pass filter (product No. 03 FCG 177). FIG.
Shows the spectral response of a UV detector operating at -2V. For comparison, IT
O / glass substrate MEH-PPV: the spectral response of the C ₆₀ photodiodes were plotted and response of UV enhanced Si photodiodes. This data shows that the polymer UV detector was sensitive to 300-400 nm UV irradiation, with a photosensitivity of ~ 150 mA / W, comparable to that of a UV enhanced silicon photodiode. The data also, MEH-PPV photoresponsive photodiode exceeds 1 was suppressed by the optical band-pass filter (10 ³ min (-over-10 ³ t
imes)).

This example demonstrates that by integrating a voltage switchable organic photodiode with a UV high frequency pass optical filter, a highly sensitive solar blind UV detector can be manufactured.

Example 17 Example 14 was repeated except that the active layer was a thin PTV layer. PTV
The spectral response of the photodiode is shown in FIG. 15a. This spectral response covers the range of 300-700 nm. That is, it covers the entire visible range. Detection of the selected color was achieved by inserting a bandpass or long wavelength filter in front of the detector. FIG. 15b shows the response of blue, green and red pixels made using a panel of color filters and an array of PTV photodiodes. The transmittance of the corresponding R, G, B color filters is shown in FIG. 15c.

This embodiment achieves R, G, B color recognition using a polymer photodiode matrix panel with a response that covers the entire visible spectrum by combining a polymer image sensor with a panel of color filters. Demonstrate what you can do.

Example 18 Following the approach shown in FIG. 5, red, green and blue (R, G, B) color detection was achieved. The material used for the active layer is a P material having a long wavelength cutoff of 500 nm.
PV, poly (dihexyloxyphenylenevinylene) "PDHPV" with a long wavelength cutoff of 600 nm, and P with a long wavelength cutoff of 700 nm
TV. From the solution in the form of the precursor, films of 1000 to 3000 mm thickness were cast. Conversion to the conjugated form was performed at a temperature of 150-230 ° C. The conjugate film thus formed was insoluble in the organic solvent. Thus, patterning these materials into dots or strips on a single substrate can be accomplished using standard photolithography, screen printing, and the like. The normalized optical response of these photodiodes is shown in FIG. In this experiment, an ITO / glass substrate that was optically transparent in the visible and opaque in the UV was used.

[0129] Selective color detection of red and green was achieved by differentiating the signals from these photodiodes (this operation can be easily performed with a readout circuit). The response difference between these photodiodes is shown in FIG. 16b. Red detection (600 ~
Has a response of 700 nm) from the signal from the PDHPV photodiode
Achieved by subtracting the signal from the PTV photodiode. Green detection (5
(With a response of 00-600 nm) was achieved by subtracting the PDHPV signal from the PPV signal. Blue detection was obtained directly from the PPV photodiode.

This example demonstrates that by patterning three photosensitive materials on a substrate having uniform optical properties, detection of selected colors of R, G, B and a full-color image sensor can be achieved.

Example 19 A voltage-switchable photodiode was manufactured using poly (p-phenylvinylene) PPV as a conjugated polymer as a photoactive material. Non-conjugated precursor solution to IT
The PPV films are spin cast on O substrates and then these PPV films are
It was changed to a conjugated form by heating at 0 ° C. for 3 hours. Al was used as the back electrode. The active area was ０．１0.15 cm ² . The IV characteristics of this photodiode in the dark and under illumination are shown in FIG. Photocurrent / dark current ratio is several mW
/ Cm ² for white light illumination, in the range of 10 ⁴ . For example, a relatively low dark current was observed with a forward bias as compared with the dark current observed with the photodiode of Example 1. This allows for light detection in both forward and reverse bias, as shown in FIG. By changing the external bias voltage, the photosensitivity can be switched on and off. For example, under white (or UV) light illumination,
The photocurrent at + 5V or -5V is 2000 times the photocurrent at + 0.95V (or 0.3V).

This example demonstrates that a photodiode can be turned on by applying a forward bias (beyond the voltage corresponding to the off state) or a reverse bias. Photodiodes that can operate with both switch polarities are useful in certain circuit designs and applications.

Example 20 A voltage-switchable photodiode having a heterojunction structure as an active layer was manufactured. These photodiodes had an ITO / donor layer / acceptor layer / metal structure. Materials used for the donor layer were MEH-PPV and PPV.
It is. Materials used in the acceptor layer comprises a C ₆₀ arranged by a physical vapor deposition is a PCBM and PCBCR arranged by drop casting (casting) or rotary casting. Data sets for MEH-PPV / C ₆₀ photodiode is shown in FIG. 18.

In these devices, a large number of bonds were observed. A built-in potential of -0.5V (forward bias assigned as positive bias to ITO) was seen in the IV curves obtained in the dark. Other joints appeared when the device was illuminated. The overall effective barrier is ~ 0.15V (sign changes). The photocurrent / dark current ratio was 10 ⁴ over a wide bias range. Voltage switchable photosensitivity was seen in both forward and reverse bias. For example, the on / off ratio of the photocurrent is 310 ³ with a bias between + 2V and + 0.15V.

This example demonstrates that a voltage-switchable photodiode can be fabricated in the form of a heterojunction using two (or more) organic semiconductors with different electronic structures. In these devices, the photosensitive mode can be achieved with both forward bias and reverse bias.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view of a voltage switchable photodiode 10 of the present invention assembled into a circuit. The photocurrent can be read by a current meter inserted into the loop.

FIG. 2 is a schematic cross-sectional view of a voltage-switchable photodiode 20 having a reverse configuration, which refers to a configuration in which a transparent electrode is in contact with a free surface of an active layer.

FIG. 3 is a schematic exploded view of a 2D image sensor 30 comprising an xy addressable passive matrix of voltage switchable photodiodes.

FIG. 4 is a schematic exploded view of a full color image sensor 40 made using an xy addressable photodiode matrix coupled to a color filter panel.

FIG. 5 is a schematic of a full color image sensor 50 fabricated using an xy addressable photodiode matrix of three photosensitive materials, each full color pixel having a different long wavelength cutoff, such as 700 nm, 600 nm and 500 nm. It is an exploded view.

FIG. 6 is a graph of photocurrent as a function of bias voltage in an ITO / MEH-PPV / Ca device.

FIG. 7 is a graph showing the transmission characteristics of PANI-CSA and PEDT-PSS conductive polymer electrodes, and also showing the visual response V (λ) of the human eye.

FIG. 8 is a graph showing a photocurrent (circle) and a dark current (square) of an ITO / MEH-PPV: PCBM / Al photodiode. Photocurrent was obtained under white light with an intensity of 〜１０10 mW / cm ² .

FIG. 9 is a graph showing the current-voltage characteristics of an ITO / P3OT / Au photodiode in the case of darkness (circle) and when irradiated at 633 nm at 10 mW / cm ² (square).

FIG. 10 is a graph of IV characteristics measured between a row electrode and a column electrode of a 7 × 40 photodiode matrix in the dark (line) and under room light illumination (circle).

FIG. 11 is a schematic diagram of a driving mechanism of a 7 × 40 photodiode matrix. This is
TO / MEH-PPV: Described in terms of a PCBM / Ag switchable photodiode.

FIG. 12 is a graph of the optical response of a voltage switchable photodiode fabricated using P3OT.

FIG. 13a is a graph of the optical response of a voltage switchable photodiode having a spectral response V (λ) simulating the spectral response of the human eye.

13b is a graphical illustration of the visual response V (λ) and the transmission of the long wavelength pass filter corresponding to FIG. 13a.

FIG. 14 is a graphical illustration of the spectral response of a solar blind UV detector operating at -2V. For comparison, ITO / glass substrate MEH-PPV: photoresponse and C ₆₀ photodiode, and the optical response of the UV enhancer Si photodiode, are plotted.

FIG. 15a is a graph of the response of a PTV photodiode.

FIG. 15b: R, G, PTV photodiodes coupled to a color filter panel.
It is a graph figure of the optical response of B light sensor.

FIG. 15c is a graph of the transmittance of the color filters used to generate the data shown in the graphs of FIGS. 15a and 15b.

FIG. 16a is a graph of the normalized spectral response of a photodiode made using PPV (open squares), PDHPV (open circles) and PTV (closed circles).

FIG. 16b is a graphical illustration of red, green and blue detection resulting from the diode response of FIG. 16a.

FIG. 17 is a graph showing the IV response of a PPV photodiode under darkness and illumination.

FIG. 18 is a graph showing the IV response of a photodiode under darkness and illumination.
The photoactive layer has a donor / acceptor bilayer structure

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, GM, HR, HU, ID, IL, IS, JP, KE, KG, KP , KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZWF term (reference) 4M118 AA10 AB10 BA30 CA02 CB14 CB20 GA02 GC08 5F049 MA01 MB08 NA20 NB05 RA02 UA11 WA03 WA09

Claims (58)

[Claims] 1. A switchable organic photodiode detector comprising a photodiode and a voltage source, the photodiode having a built-in potential, the photodiode comprising: a support substrate; A first electrode disposed on the substrate, a photoactive organic layer disposed on the first electrode, a second electrode disposed on the photoactive organic layer, the first electrode and A voltage source adapted to selectively apply a switching voltage to the second electrode, wherein the switching voltage provides a photosensitivity of 1 mA / W or more at reverse or forward bias operation, and A photodiode detector that provides near-zero photosensitivity with a cut-off bias of a magnitude substantially equivalent to the built-in potential. 2. The method according to claim 1, wherein the operation bias is an operation reverse.
2. The photodiode detector of claim 1, wherein the photodiode detector is (verse) a bias. 3. The method according to claim 2, wherein the operation bias is an operation order (operation fo).
rward) bias. 4. The readout circuit using the organic photodiode detector according to claim 1, wherein the operating bias is larger than 1 V, indicating an on state of the photodiode, and the detector is configured to detect the on state of the photodiode. A readout circuit having a photosensitivity of 1 mA / W or greater in a state and wherein the cutoff bias represents an off-state of the photodiode wherein the cutoff bias is equivalent to a zero optical response at the output of the readout circuit. 5. A photodiode array comprising a plurality of the photodiode detectors of claim 1, wherein the photodiodes of the detectors are arranged in an array, each of the photodiodes being a pixel of the array. A photodiode array that is selectively addressable as a. 6. The array is a linear array having a common anode and individual cathodes, the common anode being connected to a fixed anode voltage level, the individual cathode being greater than the anode voltage and 6. The photodiode array of claim 5, wherein the photodiode array is connected to a switchable voltage that is variable between a photosensitizing voltage and a non-photosensitizing second voltage. 7. The array is a linear array having a common cathode and individual anodes, the common cathode being connected to a constant cathode voltage, wherein the individual anodes are lower than the cathode voltage and are photosensitive. 6. The photodiode array of claim 5, wherein the photodiode array is connected to a switchable voltage that is variable between a voltage that provides photosensitivity and a second voltage that does not provide light sensitivity. 8. The array according to claim 1, wherein said array comprises at least one row of photodiodes;
At least one column of photodiodes, wherein each row has an associated common anode, each column has an associated common cathode, and wherein said first electrode of each photodiode in a row comprises the common anode. And the second electrode of each photodiode in the column is connected to the common cathode, and the voltage source applies the switching voltage to at least one common anode and at least one common cathode. 6. The photodiode array of claim 5, wherein the photodiode array is adapted to selectively activate at least one pixel of the array. 9. The method of claim 8, wherein the switching voltage is applied to a plurality of common anodes and at least one common cathode, thereby selectively activating at least one column of pixels of the array. A photodiode array according to claim 1. 10. The method of claim 8, wherein the switching voltage is applied to a plurality of common cathodes and at least one common anode, thereby selectively activating at least one row of pixels of the array. A photodiode array according to claim 1. 11. The sequential readout of the selectively activated columns is performed by applying an operating bias voltage to a common cathode associated with the selected column and all common anodes. Thereby sequentially activating selected columns of photodiodes, the operating voltage providing each photodiode of the selected columns with a photosensitivity of 1 mA / W or more; And applying a cut-off voltage to all the anodes, the cut-off voltage having a magnitude equivalent to the built-in potential, and a photo of all columns other than the selected column. 10. The method of claim 9, further comprising the step of sensitizing the diode to near zero, and sequentially reading the generated output of a selected column of the photodiode. Photodiode array. 12. A sequential readout of the selectively activated rows is performed, wherein the selective readout applies an operating bias voltage to a common anode associated with the selected row and to all common cathodes. By sequentially activating selected rows of photodiodes, the operating voltage providing each photodiode in the selected rows with a sensitivity of 1 mA / W or more, and the remaining anodes And applying a cut-off voltage to all the cathodes, the cut-off voltage having a magnitude equivalent to the built-in potential, and a photo of all rows other than the selected row. 10. The method of claim 9, further comprising the step of providing the diodes with near-zero photosensitivity and sequentially reading out the generated output of a selected row of the photodiodes. Photodiode array. 13. A scannable array of voltage-switchable organic photodiodes, each having a built-in potential and a predetermined photosensitive range, the array comprising: a support substrate; A first electrode layer including at least one linear electrode disposed on the support substrate along a first direction; a photoactive organic material layer disposed on the linear electrode; A second electrode layer including a plurality of linear electrodes arranged along a second direction transverse to the first direction; at least one electrode of the first electrode layer; and the second electrode layer And a voltage source adapted to apply a switching voltage to at least one electrode of the at least one selected photodiode, whereby the at least one selected photodiode has an operating bias of greater than or equal to 1 mA / W. Feeling Together give gender, to sensitize near zero in the built-in potential substantially equivalent to the size of the cut-off bias, scannable array. 14. The operation bias according to claim 13, wherein the operation bias is an operation reverse bias.
2. The scannable array of claim 1. 15. The operation bias according to claim 13, wherein the operation bias is an operation forward bias.
2. The scannable array of claim 1. 16. An array comprising: a plurality of common anodes in a first direction;
6. The photodiode array according to claim 5, wherein the photodiode array is a two-dimensional array having a plurality of common cathodes in the directions of. 17. The signal from the photodiode array does not sensitize all common cathodes and all common anodes except the read common cathode biased to a sensitizing voltage. 17. The photodiode array according to claim 16, read by means for applying a given voltage level. 18. A method in which the signal from the photodiode array does not sensitize all common anodes except the common anode being read and all common cathodes that are biased to a sensitizing voltage. 18. The photodiode array according to claim 17, read by means for applying a given voltage level. 19. The individual photodiodes coupled to the common electrode being read are individually read by means for applying a bias voltage that sensitizes the individual electrodes to the individual electrodes. 19. The photodiode array according to 18. 20. An organic photodiode detector including a photodiode and a voltage source, the photodiode having a built-in potential and a predetermined photosensitive range responsive to incident radiation, wherein the photodiode has A diode, a support substrate, a first electrode disposed on the support substrate, a photoactive organic layer disposed on the first electrode, and a second electrode disposed on the photoactive organic layer. An electrode; and a voltage source adapted to apply an operating bias voltage to the first electrode and the second electrode, wherein the bias voltage operates to change the predetermined photosensitive range. , Organic photodiode detector. 21. The operation bias according to claim 20, wherein the operation bias is an operation reverse bias.
4. The organic photodiode detector according to 4. 22. The operation bias according to claim 20, wherein the operation bias is an operation forward bias.
4. The organic photodiode detector according to 4. 23. The photosensitivity of the photodiode is 1 mA / W or more when the voltage source is operated reversely, and is close to zero when the cut-off bias is substantially equivalent to the built-in potential. 22. The voltage source is selectively switchable between the operational reverse bias and the cutoff bias.
4. The organic photodiode detector according to 4. 24. A readout circuit using the organic photodiode detector according to claim 23, wherein the operation reverse bias is in a range of 2 to 15 V, and indicates an on state of the photodiode. Has a photosensitivity of 1 mA / W or more in the on state and the cutoff bias represents an off state of the photodiode, which is equivalent to a zero optical response at the output of the digital readout circuit. . 25. A photodiode array comprising a plurality of the photodiodes of claim 20, wherein the photodiodes are arranged in an array, each of the photodiodes being selectively addressed as a pixel of the array. A photodiode array is possible. 26. The array includes at least one row of photodiodes and at least one column of photodiodes, each row having an associated common anode, and each column having an associated common cathode. And wherein the first electrode of each photodiode in a row is connected to the common anode, the second electrode of each photodiode in a column is connected to the common cathode, and the voltage source is at least one 26. The photodiode array of claim 25, wherein the photodiode array is adapted to apply the bias voltage to a common anode and at least one common cathode, thereby selectively activating at least one pixel of the array. 27. The method of claim 26, wherein the bias voltage is applied to a plurality of common anodes and at least one common cathode, thereby selectively activating at least one column of pixels of the array. A photodiode array according to claim 1. 28. The organic photodiode detector according to claim 20, wherein the support substrate and the first electrode are substantially transparent to incident radiation. 29. The organic photodiode detector of claim 20, wherein said second electrode is substantially transparent to incident radiation. 30. The organic photodiode detector according to claim 20, wherein the photoactive organic layer is made of a semiconductive conjugated polymer. 31. The organic photodiode detector of claim 30, wherein the semiconductive conjugated polymer is in a doped form. 32. The semiconductive conjugated polymer may be in an intrinsic neutral state (intrin
31. The organic photodiode detector of claim 30, wherein the detector is a sic neutral state. 33. The semiconductive conjugated polymer may be poly (phenylenevinylene) and its derivative, polythiophene and its derivative, poly (thiophenvinylene) and its derivative, polyacetylene and its derivative, polyisothianaphen and its derivative, polypyrrole and Poly (2,5-thienylenevinylene) and its derivatives, poly (p-phenylene) and its derivatives, polyfluorene and its derivatives, polycarbazole and its derivatives, poly (1,6-heptadiyne) and its derivatives, 31. The organic photodiode detector of claim 30, wherein the detector is selected from polyquinolene and derivatives thereof, and polyaniline and derivatives thereof. 34. The photoactive organic layer comprises a donor / acceptor polyblend, wherein the donor is poly (phenylenevinylene), polythiophene, poly (
Thiophene vinylene), and is selected from its soluble derivatives, such as MEH-PPV, the acceptor, poly (cyano vinylene), fullerene molecules such as C _60, and is selected a functional derivative thereof PCMB and PCBCR, from 21. The organic photodiode detector according to claim 20, wherein 35. The organic photodiode detector of claim 20, wherein said photoactive organic layer comprises a polymer / polymer polyblend. 36. The organic photodiode detector of claim 20, wherein the photoactive organic layer comprises a polymer / (organic molecule) polyblend. 37. The optical active organic material layer, anthracene and its derivatives, tetracene and its derivatives, phthalocyanine and its derivatives, pinacyanol and its derivatives, fullerene C ₆₀ and derivatives thereof, thiophene and its derivatives, phenylene and its derivatives, triphenylene , and includes 2,3,6,7,10,11 hexa-hexyl derivatives thereof including thio triphenylene, 6T / C ₆₀ and derivatives thereof, 6T / pinacyanol and derivatives thereof, phthalocyanine / o-chloranil, and the derivatives thereof blend, anthracene / C ₆₀ and derivatives thereof, and anthracene / o-chloranil and its derivatives, made from a material selected from organic photodiode detector of claim 20. 38. The photoactive organic layer is configured in a semiconductive heterojunction structure in which at least one set of donor and acceptor regions is disposed.
4. The organic photodiode detector according to 4. 39. The said heterojunction structure is poly (phenylene vinylene) and its derivative, polythiophene and its derivative, poly (thiophenvinylene) and its derivative, polyacetylene and its derivative, polyisothianaphen and its derivative, polypyrrole and its Derivatives, poly (2,5-thienylenevinylene) and its derivatives, poly (p-phenylene) and its derivatives, polyfluorene and its derivatives, polycarbazole and its derivatives, poly (1,6-heptadiyne) and its derivatives, polyquinolene And its derivatives, polyaniline and its derivatives, anthracene and its derivatives, tetracene and its derivatives, phthalocyanine and its derivatives, pinacyanol and its derivatives, fullerene C ₆₀ and its derivatives, thiophene and its derivatives, phenylene and its derivatives, triphenylene and its derivatives including 2,3,6,7,10,11-hexahexylthiotriphenylene, 6T / C ₆₀ and its derivatives, 6T / pinacyanol and its derivatives, phthalocyanine / o-chloranil and its derivatives, anthracene / C ₆₀ and derivatives thereof, and anthracene / o-chloranil and its derivatives, comprises a polymer selected from the organic photodiode detector of claim 38 vessel. 40. The organic photodiode detector according to claim 20, wherein the photoactive organic layer contains an optically inactive organic additive. 41. The organic photodiode detector according to claim 40, wherein the optically inactive organic additive is an anionic surfactant. 42. The optically inactive organic additive is an organic electrolyte.
An organic photodiode detector according to claim 40. 43. The method according to claim 43, wherein the first and / or second electrodes (or both) are poly (
21. The organic photodiode detector according to claim 20, comprising a conductive polymer selected from aniline-camphorsulfonic acid), poly (ethylenedioxythiophene) -polystyrenesulfonate, and polypyrrole. 44. The method of claim 43, wherein the first electrode comprises a conductive polymer selected from poly (aniline-camphorsulfonic acid), poly (ethylenedioxythiophene) -polystyrenesulfonate, and polypyrrole. Organic photodiode detector. 45. The method of claim 20, wherein the second electrode comprises a conductive polymer selected from poly (aniline-camphorsulfonic acid), poly (ethylenedioxythiophene) -polystyrenesulfonate, and polypyrrole. Organic photodiode detector. 46. The organic photodiode detector comprises an optical filter layer adapted to limit transmission of incident radiation to a predetermined wavelength range.
4. The organic photodiode detector according to 4. 47. The organic photodiode detector according to claim 46, wherein the supporting substrate operates as the optical filter layer. 48. The system of claim 4, wherein the wavelength range is the human visible spectrum.
7. The organic photodiode detector according to 6. 49. The pixel is adapted for selection by setting a voltage bias pattern that suppresses crosstalk during readout.
4. The organic photodiode detector according to 4. 50. A photodiode comprising: a first sensor means for detecting radiation in the red range; a second sensor means for detecting radiation in the green range;
Organic photodiode detector according to claim 20, comprising a pixel having a third sensor means for detecting radiation in the blue range. 51. The organic photodiode detector of claim 50, wherein said pixels comprise a color filter panel for providing selective color transmission. 52. The first sensor means includes a photodiode sensitive to wavelengths shorter than 700 nm; the second sensor means includes a photodiode sensitive to wavelengths shorter than 600 nm; The organic photodiode detector according to claim 50, wherein the sensor means comprises an active layer sensitive to blue. 53. The organic photodiode detector comprises a scintillation material adapted to emit photons in response to ionized particles.
The organic photodiode detector according to 0. 54. The scintillation material is a phosphor layer.
4. The organic photodiode detector according to 3. 55. The organic photodiode detector of claim 53, wherein the ionized particles are selected from high energy photons, electrons, x-rays, beta particles, and gamma rays. 56. The organic photodiode detector of claim 20, wherein the organic photodiode detector comprises a layer that generates mobile electrons and holes in response to ionized particles. 57. The organic photodiode detector of claim 53, wherein said wavelength range is the UV spectrum. 58. The organic photodiode detector of claim 20, wherein the organic photodiode is formed using a soluble semiconductive conjugated polymer cast from a solution.