Photoelectric conversion devices and organic sensors and electronic devices

A photoelectric conversion device includes a first electrode and a second electrode facing each other, a photoelectric conversion layer between the first electrode and the second electrode and configured to absorb light in at least one part of a wavelength spectrum of light and to convert it into an electric signal, and an inorganic nanolayer between the first electrode and the photoelectric conversion layer and including a lanthanide element, calcium (Ca), potassium (K), aluminum (Al), or an alloy thereof. An organic CMOS image sensor may include the photoelectric conversion device. An electronic device may include the organic CMOS image sensor.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2018-0139824 filed in the Korean Intellectual Property Office on Nov. 14, 2018, the entire contents of which are incorporated herein by reference.

BACKGROUND

Photoelectric conversion devices, organic sensors, and electronic devices are disclosed.

2. Description of the Related Art

A photoelectric conversion device may receive incident light and converts the received incident light into an electric signal. A photoelectric conversion device may include a photodiode and a phototransistor, and may be applied to (“included in”) an organic sensor, a photodetector, a solar cell, or the like.

Organic sensors may have higher resolutions and thus may have smaller pixel sizes. Organic sensors may include silicon photodiodes. A sensitivity of a silicon photodiode in an organic sensor may be deteriorated based on reduced pixel size of the organic sensor the absorption area of the silicon photodiode may be reduced. Accordingly, organic materials that are capable of replacing silicon in photodiodes of organic sensors have been researched.

An organic material has a high extinction coefficient and is configured to selectively absorb light in a particular wavelength spectrum of light depending on a molecular structure of the organic material, and thus may simultaneously replace a photodiode and a color filter of an organic sensor and resultantly improve sensitivity of the organic sensor and contribute to high integration of the organic sensor.

However, since such organic materials exhibit different characteristics from those of silicon due to high binding energy and a recombination behavior associated with such organic materials, the characteristics of the organic materials are difficult to precisely predict, and thus required properties of a photoelectric conversion device may not be easily controlled.

SUMMARY

Some example embodiments provide one or more photoelectric conversion devices capable of improving charge extraction efficiency.

Some example embodiments provide organic sensors including one or more of the photoelectric conversion device.

Some example embodiments provide electronic devices including the one or more photoelectric conversion devices or the one or more organic sensors.

According to some example embodiments, a photoelectric conversion device may include a first electrode and a second electrode facing each other, a photoelectric conversion layer between the first electrode and the second electrode, the photoelectric conversion layer configured to absorb light in at least one part of a wavelength spectrum of light and to convert the absorbed light into an electric signal, and an inorganic nanolayer between the first electrode and the photoelectric conversion layer, the inorganic nanolayer including a lanthanide element, calcium (Ca), potassium (K), aluminum (Al), or an alloy thereof.

The inorganic nanolayer may include the lanthanide element, and the lanthanide element includes ytterbium (Yb).

The inorganic nanolayer may be in contact with the first electrode.

One surface of the inorganic nanolayer may be in contact with the first electrode, and another, opposite surface of the inorganic nanolayer may be in contact with the photoelectric conversion layer.

The first electrode may include a transparent electrode having a light transmittance of greater than or equal to about 80%, or a reflective electrode having a light transmittance of less than about 10%.

The first electrode may include the transparent electrode, and the transparent electrode includes at least one of an oxide conductor and a carbon conductor.

A thickness of the inorganic nanolayer may be less than or equal to about 5 nm.

A thickness of the inorganic nanolayer may be less than or equal to about 2 nm.

The first electrode may be a cathode and the second electrode is an anode.

According to some example embodiments, a photoelectric conversion device may include a first electrode, the first electrode including a conductor, the conductor being a transparent conductor having a light transmittance of greater than or equal to about 80%, or a reflective conductor having a light transmittance of less than about 10%. The photoelectric conversion device may include a photoelectric conversion layer on the first electrode, the photoelectric conversion layer configured to absorb light in at least one part wavelength spectrum of light and to convert the absorbed light into an electric signal, and a second electrode on the photoelectric conversion layer. A surface of the first electrode facing the photoelectric conversion layer may be covered by an inorganic nanolayer, the inorganic nanolayer having a thickness of less than or equal to about 5 nm. An effective work function at the surface of the first electrode facing the photoelectric conversion layer may be less than a work function of the conductor.

A difference between the work function of the conductor and the effective work function at the surface of the first electrode facing the photoelectric conversion layer may be greater than or equal to about 0.5 eV.

The work function of the conductor may be greater than or equal to about 4.5 eV, and the effective work function at the surface of the first electrode facing the photoelectric conversion layer may be less than or equal to about 4.0 eV.

The effective work function at the surface of the first electrode facing the photoelectric conversion layer may be less than or equal to about 3.0 eV.

The inorganic nanolayer may include an inorganic material, and the inorganic material includes a lanthanide element, calcium (Ca), potassium (K), aluminum (Al), or an alloy thereof.

The inorganic material may include the lanthanide element, and the lanthanide element includes ytterbium (Yb).

The transparent conductor may include an oxide conductor or a carbon conductor.

The inorganic nanolayer may have a thickness of less than or equal to about 2 nm.

The first electrode may be a cathode and the second electrode may be an anode.

An electronic device may include the photoelectric conversion device.

An organic sensor may include the photoelectric conversion device. The organic sensor may be an organic complementary metal-oxide-semiconductor (CMOS) sensor. An electronic device may include the organic sensor such as the organic CMOS image sensor.

According to some example embodiments, an organic complementary metal-oxide-semiconductor (CMOS) image sensor may include a semiconductor substrate; and a plurality of photoelectric conversion devices on the semiconductor substrate, the plurality of photoelectric conversion devices configured to convert different wavelength spectra of light into electric signals, respectively. Each photoelectric conversion device of the plurality of photoelectric conversion devices may include a first electrode and a second electrode facing each other, the first electrode including a conductor, the conductor being a transparent conductor having a light transmittance of greater than or equal to about 80%, or a reflective conductor having a light transmittance of less than about 10%; and a photoelectric conversion layer between the first electrode and the second electrode, the photoelectric conversion layer configured to absorb light in at least one part of a wavelength spectrum of light and to convert the absorbed light into an electric signal. A surface of the first electrode facing the photoelectric conversion layer may be covered by an inorganic nanolayer, the inorganic nanolayer having a thickness of less than or equal to about 5 nm. An effective work function at the surface of the first electrode facing the photoelectric conversion layer may be less than a work function of the conductor. The plurality of photoelectric conversion devices may include different photoelectric conversion layers configured to absorb different wavelength spectra of light.

The plurality of photoelectric conversion devices may be arranged horizontally on the semiconductor substrate, such that the plurality of photoelectric conversion devices overlap each other in a direction extending parallel to a top surface of the semiconductor substrate.

The plurality of photoelectric conversion devices may be arranged vertically on the semiconductor substrate, such that the plurality of photoelectric conversion devices overlap each other in a direction extending perpendicular to a top surface of the semiconductor substrate, and one photoelectric conversion device of the plurality of photoelectric conversion devices overlaps with a limited portion of another photoelectric conversion device of the plurality of photoelectric conversion devices in the direction extending perpendicular to the top surface of the semiconductor substrate.

The inorganic nanolayer may include an inorganic material, and the inorganic material includes a lanthanide element, calcium (Ca), potassium (K), aluminum (Al), or an alloy thereof.

The inorganic nanolayer may include the lanthanide element, and the lanthanide element may include ytterbium (Yb).

A difference between the work function of the conductor and the effective work function at the surface of the first electrode facing the photoelectric conversion layer may be greater than or equal to about 0.5 eV.

The work function of the conductor may be greater than or equal to about 4.5 eV, and the effective work function at the surface of the first electrode facing the photoelectric conversion layer may be less than or equal to about 4.0 eV.

An electronic device may include the organic sensor.

According to some example embodiments, an organic complementary metal-oxide-semiconductor (CMOS) image sensor may include a semiconductor substrate; a photo-sensing device integrated in the semiconductor substrate, the photo-sensing device configured to convert a first wavelength spectrum of light into electric signals; and a photoelectric conversion device on the semiconductor substrate, the photoelectric conversion device configured to convert a second wavelength spectrum of light into electric signals. The photoelectric conversion device may include a first electrode and a second electrode facing each other, the first electrode including a conductor, the conductor being a transparent conductor having a light transmittance of greater than or equal to about 80%, or a reflective conductor having a light transmittance of less than about 10%, and a photoelectric conversion layer between the first electrode and the second electrode, the photoelectric conversion layer configured to absorb light in at least one part of a wavelength spectrum of light and to convert the absorbed light into an electric signal. A surface of the first electrode facing the photoelectric conversion layer may be covered by an inorganic nanolayer, the inorganic nanolayer having a thickness of less than or equal to about 5 nm. An effective work function at the surface of the first electrode facing the photoelectric conversion layer may be less than a work function of the conductor.

The organic CMOS image sensor may further include a color filter configured to selectively transmit a particular wavelength spectrum of light to the photo-sensing device, such that the photo-sensing device is configured to absorb the particular wavelength spectrum of light.

The inorganic nanolayer may include an inorganic material, and the inorganic material may include a lanthanide element, calcium (Ca), potassium (K), aluminum (Al), or an alloy thereof.

The inorganic nanolayer may include the lanthanide element, and the lanthanide element includes ytterbium (Yb).

A difference between the work function of the conductor and the effective work function at the surface of the first electrode facing the photoelectric conversion layer may be greater than or equal to about 0.5 eV.

The work function of the conductor may be greater than or equal to about 4.5 eV, and the effective work function at the surface of the first electrode facing the photoelectric conversion layer may be less than or equal to about 4.0 eV.

An electronic device may include the organic CMOS image sensor of claim30.

DETAILED DESCRIPTION

Hereinafter, example embodiments of the present disclosure will be described in detail so that a person skilled in the art would understand the same. However, this disclosure may be embodied in many different forms and is not to be construed as limited to the example embodiments set forth herein.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity.

As used herein, when a definition is not otherwise provided, “hetero” may refer to one including 1 to 4 heteroatoms selected from N, O, S, Se, Te, Si, and P.

As used herein, when a definition is not otherwise provided, “heterocyclic group” is a generic concept of a heteroaryl group, may include an aromatic and non-aromatic ring including at least one heteroatom, and may include at least one heteroatom selected from N, O, S, P, and Si instead of carbon (C) in a cyclic compound such as an aryl group, a cycloalkyl group, a fused ring thereof, or a combination thereof. When the heterocyclic group is a fused ring, the entire ring or each ring of the heterocyclic group may include one or more heteroatoms.

Hereinafter, “combination” may refer to a mixture of two or more and a stack structure of two or more.

Hereinafter, a work function or an energy level is expressed as an absolute value from a vacuum level. In addition, when the work function or the energy level is referred to be deep, high, or large, it may have a large absolute value from “0 eV” of the vacuum level while when the work function or the energy level is referred to be shallow, low, or small, it may have a small absolute value from “0 eV” of the vacuum level.

Hereinafter, a photoelectric conversion device according to some example embodiments is described.

FIG. 1is a cross-sectional view showing a photoelectric conversion device according to some example embodiments.

Referring toFIG. 1, a photoelectric conversion device100according to some example embodiments includes a first electrode10, a second electrode20, a photoelectric conversion layer30, and an inorganic nanolayer40.

A substrate (not shown) may be disposed at the side of the first electrode10or the second electrode20. The substrate may be for example made of an inorganic material such as glass, an organic material such as polycarbonate, polymethylmethacrylate, polyethyleneterephthalate, polyethylenenaphthalate, polyamide, polyethersulfone, or a combination thereof, or a silicon wafer. The substrate may be omitted.

As shown, the first electrode10and the second electrode20are facing each other. One of the first electrode10and the second electrode20is an anode and the other is a cathode. In some example embodiments, the first electrode10may be a cathode and the second electrode20may be an anode. In another example, the first electrode10may be an anode and the second electrode20may be a cathode.

At least one of the first electrode10and the second electrode20may be a transparent electrode, such that the at least one of the first electrode10and the second electrode20includes a transparent conductor. Herein, the transparent electrode may include a transparent conductor having a high light transmittance of greater than or equal to about 80% and may not include for example a semi-transparent electrode for microcavity. The transparent electrode may include for example a transparent conductor that includes at least one of an oxide conductor and a carbon conductor. The oxide conductor may include for example at least one of indium tin oxide (ITO), indium zinc oxide (IZO), zinc tin oxide (ZTO), aluminum tin oxide (AITO), and aluminum zinc oxide (AZO) and the carbon conductor may at least one of graphene and carbon nanostructure.

One of the first electrode10and the second electrode20may be a reflective electrode, such that the at least one of the first electrode10and the second electrode20includes a reflective conductor. Here, the reflective electrode may include, in some example embodiments, a reflective conductor having a light transmittance of less than about 10% or high reflectance of less than or equal to about 5%. The reflective electrode may include a reflective conductor such as a metal and may include, for example aluminum (Al), silver (Ag), gold (Au), or an alloy thereof.

In view of the above, it will be understood that the first electrode10and/or the second electrode20may include a conductor, where the conductor may be a transparent conductor or a reflective conductor. A conductor that is a transparent conductor may have a light transmittance of greater than or equal to about 80%. A conductor that is a reflective conductor may having a light transmittance of less than about 10%.

In some example embodiments, the first electrode10may be a transparent electrode having a light transmittance of greater than or equal to about 80% or a reflective electrode having a light transmittance of less than about 10%.

The photoelectric conversion layer30, which, as shown, is between the first electrode10and the second electrode20, may be configured to absorb light in at least one part of a wavelength spectrum of light and convert the absorbed light into an electric signal, and for example one of light in a green wavelength spectrum of light (hereinafter, referred to as “green light”), light in a blue wavelength spectrum of light (hereinafter, referred to as “blue light”), light in a red wavelength spectrum of light (hereinafter, referred to as “red light”), light in an ultraviolet wavelength spectrum of light (hereinafter, referred to as ‘ultraviolet light’), and light in an infrared wavelength spectrum of light (hereinafter, referred to as “infrared light”) into an electric signal.

In some example embodiments, the photoelectric conversion layer30may be configured to selectively absorb at least one of the green light, the blue light, the red light, and the infrared light. Herein, the selective absorption of at least one from the green light, the blue light, the red light, and the infrared light means that a light-absorption spectrum has a peak absorption wavelength (λmax) in one of about 500 nm to about 600 nm, greater than or equal to about 380 nm and less than about 500 nm, greater than about 600 nm and less than or equal to about 700 nm, and greater than about 700 nm, and a light-absorption spectrum in the corresponding wavelength spectrum of light may be remarkably higher than those in the other wavelength spectra of light.

The photoelectric conversion layer30may include a semiconductor material that is at least one p-type semiconductor and/or at least one n-type semiconductor, where the semiconductor material forms a pn junction with the first organic material of the photoelectric conversion layer30and may produce excitons by receiving light from outside and then separate the produced excitons into holes and electrons.

The p-type semiconductor and the n-type semiconductor may be independently light-absorbing materials, and for example at least one of the p-type semiconductor and the n-type semiconductor may be an organic light-absorbing material. In some example embodiments, at least one of the p-type semiconductor and the n-type semiconductor may be a wavelength-selective light-absorbing material that selectively absorbs light in a particular (or, alternatively, predetermined) wavelength spectrum of light, and for example at least one of the p-type semiconductor and the n-type semiconductor may be a wavelength-selective organic light-absorbing material. The p-type semiconductor and the n-type semiconductor may have a peak absorption wavelength (λmax) in the same wavelength spectrum of light or in a different wavelength spectrum of light.

In some example embodiments, the p-type semiconductor may be an organic material having a core structure including an electron donating moiety, a pi conjugation linking group, and an electron accepting moiety.

The p-type semiconductor may be for example represented by Chemical Formula 1, but is not limited thereto.
EDG-HA-EAG  [Chemical Formula 1]

In Chemical Formula 1,

HA is a C2 to C30 heterocyclic group having at least one of S, Se, Te, and Si,

EDG is an electron-donating group, and

EAG is an electron accepting group.

In some example embodiments, the p-type semiconductor represented by Chemical Formula 1 may be for example represented by Chemical Formula 1A.

In Chemical Formula 1A,

Ar may be a substituted or unsubstituted C6 to C30 arylene group, a substituted or unsubstituted C3 to C30 heterocyclic group, or a fused ring of the foregoing two or more,

Ar1aand Ar2amay independently be a substituted or unsubstituted C6 to C30 aryl group or a substituted or unsubstituted C3 to C30 heteroaryl group,

Ar1aand Ar2amay independently be present alone or may be linked with each other to form a fused ring, and

R1ato R1a, Ra, and Rbmay independently be hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C1 to C6 alkoxy group, a halogen, or a cyano group.

In some example embodiments, in Chemical Formula 1A, Ar1aand Ar2amay independently be one of a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, a substituted or unsubstituted phenanthrenyl group, a substituted or unsubstituted pyridinyl group, a substituted or unsubstituted pyridazinyl group, a substituted or unsubstituted pyrimidinyl group, a substituted or unsubstituted pyrazinyl group, a substituted or unsubstituted quinolinyl group, a substituted or unsubstituted isoquinolinyl group, a substituted or unsubstituted naphthyridinyl group, a substituted or unsubstituted cinnolinyl group, a substituted or unsubstituted quinazolinyl group, a substituted or unsubstituted phthalazinyl group, a substituted or unsubstituted benzotriazinyl group, a substituted or unsubstituted pyridopyrazinyl group, a substituted or unsubstituted pyridopyrimidinyl group, and a substituted or unsubstituted pyridopyridazinyl group.

In some example embodiments, Ar1aand Ar2aof Chemical Formula 1A may be linked with each other to form a ring or in some example embodiments, Ar1aand Ar2amay be linked with each other by one of a single bond, —(CR9Rh)n2— (n2 is 1 or 2), —O—, —S—, —Se—, —N═, —NRi—, —SiRjRk—, and —GeRlRm— to form a ring. Herein, Rgto Rmmay independently be hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C1 to C6 alkoxy group, a halogen, or a cyano group.

In some example embodiments, the p-type semiconductor represented by Chemical Formula 1 may be for example represented by Chemical Formula 1B.

In Chemical Formula 1B,

Ar3may be a substituted or unsubstituted C6 to C30 arylene group, a substituted or unsubstituted C3 to C30 heterocyclic group, or a fused ring of the foregoing two or more,

R1to R3may independently be one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, a cyano-containing group, and a combination thereof,

G may be one of a single bond, —O—, —S—, —Se—, —N═, —(CRfRg)k—, —NRh—, —SiRiRi—, —GeRkRl—, —(C(Rm)═C(Rn))—, and SnRoRp, wherein Rf, Rg, Rh, Ri, Rj, Rk, Rl, Rm, Rn, Ro, and Rpmay independently be one of hydrogen, a halogen, a substituted or unsubstituted C1 to C10 alkyl group, a substituted or unsubstituted C1 to C10 alkoxy group, and a substituted or unsubstituted C6 to C12 aryl group, Rfand Rg, Riand Rj, Rkand Rl, Rmand Rn, and Roand Rpmay independently be present alone or may be linked with each other to provide a ring, and k may be 1 or 2,

R6ato R6dand R7ato R7dmay independently be one of hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group, a cyano-containing group, and a combination thereof,

R6ato R6dmay independently be present alone or adjacent two thereof may be linked with each other to form a fused ring, and

R7ato R7dmay independently be present alone or adjacent two thereof may be linked with each other to form a fused ring.

In some example embodiments, Ar3 of Chemical Formula 1B may be benzene, naphthylene, anthracene, thiophene, selenophene, tellurophene, pyridine, pyrimidine, or a fused ring of the foregoing two or more.

The n-type semiconductor may be for example fullerene or a fullerene derivative, but is not limited thereto.

The photoelectric conversion layer30may be an intrinsic layer (an l layer) wherein the p-type semiconductor and the n-type semiconductor are mixed as a bulk heterojunction. Herein, the p-type semiconductor and the n-type semiconductor may be mixed in a volume ratio of about 1:9 to about 9:1, for example about 2:8 to about 8:2, about 3:7 to about 7:3, about 4:6 to about 6:4, or about 5:5.

The photoelectric conversion layer30may be a bilayer including a p-type layer including the p-type semiconductor and an n-type layer including the n-type semiconductor. Herein, a thickness ratio of the p-type layer and the n-type layer may be about 1:9 to about 9:1, for example about 2:8 to about 8:2, about 3:7 to about 7:3, about 4:6 to about 6:4, or about 5:5.

The photoelectric conversion layer30may further include a p-type layer and/or an n-type layer in addition to the intrinsic layer. The p-type layer may include the p-type semiconductor and the n-type layer may include the n-type semiconductor. In some example embodiments, they may be included in various combinations of p-type layer/l layer, l layer/n-type layer, p-type layer/l layer/n-type layer, and the like.

The inorganic nanolayer40may be disposed between the first electrode10and the photoelectric conversion layer30and may be for example in contact with the first electrode10. As shown inFIG. 1, a surface10sof the first electrode10that faces the photoelectric conversion layer30may be covered by the inorganic nanolayer40. In some example embodiments, one surface of the inorganic nanolayer40may be in contact with the first electrode10and another, opposite surface of the inorganic nanolayer40may be in contact with the photoelectric conversion layer30. It will be understood that, in some example embodiments, the inorganic nanolayer40may not be in contact with the first electrode10.

The inorganic nanolayer40may be a very thin film of a several nanometers in thickness and may have a thickness of, for example, less than or equal to about 5 nm, less than or equal to about 3 nm, or less than or equal to about 2 nm. The inorganic nanolayer40may have, for example a thickness of about 1 nm to about 5 nm, about 1 nm to about 3 nm, or about 1 nm to about 2 nm.

The inorganic nanolayer40may include an inorganic material having a lower work function than the first electrode10. In some example embodiments, a work function of the inorganic nanolayer40may be less than a work function of the first electrode10by about 0.5 eV or greater. Restated, a difference between the work function of the conductor (e.g., the transparent conductor or the reflective conductor) of the first electrode10and the effective work function at the surface10sof the first electrode10facing the photoelectric conversion layer30may be greater than or equal to about 0.5 eV. In some example embodiments, the work function of the first electrode10(e.g., the work function of the conductor (e.g., transparent conductor or reflective conductor) of the first electrode10) may be greater than or equal to about 4.5 eV and the work function of the inorganic nanolayer40may be less than or equal to about 4.0 eV. In some example embodiments, the work function of the first electrode10may be greater than or equal to about 4.5 eV and the work function of the inorganic nanolayer40may be less than or equal to about 3.5 eV. In some example embodiments, the work function of the first electrode10may be greater than or equal to about 4.5 eV and the work function of the inorganic nanolayer40may be less than or equal to about 3.0 eV. In some example embodiments, the work function of the first electrode10may be greater than or equal to about 4.5 eV and the work function of the inorganic nanolayer40may be less than or equal to about 2.8 eV. In some example embodiments, the work function of the first electrode10may be about 4.5 eV to about 5.0 eV and the work function of the inorganic nanolayer40may be about 1.5 eV to about 4.0 eV, about 1.5 eV to about 3.5 eV, about 1.5 eV to about 3.0 eV, or about 1.5 eV to about 2.8 eV.

In some example embodiments, the inorganic nanolayer40may be made of a material which satisfies the above-described work function and simultaneously may be formed by thermal evaporation. Since the inorganic nanolayer40is formed by thermal evaporation as described above, it is possible to prevent the photoelectric conversion layer30from being thermally and physically damaged in its formation process and/or the subsequent process of the inorganic nanolayer40, and thus to prevent its performance from being deteriorated due to degradation of the photoelectric conversion layer30, thereby improving the performance of the photoelectric conversion device100.

An inorganic material that may satisfy such characteristics, and thus an inorganic material included in the inorganic nanolayer40, may include, in some example embodiments, a lanthanide element, calcium (Ca), potassium (K), aluminum (Al), or an alloy thereof. The lanthanide element may include, for example ytterbium (Yb).

As described above, the inorganic nanolayer40may be in contact with the surface of the first electrode10between the first electrode10and the photoelectric conversion layer30, and it may have a thin thickness compared with the first electrode10. Accordingly, the inorganic nanolayer40may function as a surface-treatment layer of the first electrode10on the surface of the first electrode10facing the photoelectric conversion layer30and may control an effective work function of the first electrode10on the surface of the first electrode10facing the photoelectric conversion layer30. Herein, the effective work function may be a work function at the interface of the two layers in a structure where the two layers having different electrical characteristics are in contact with each other. The effective work function of the first electrode10at the interface of the first electrode10and the photoelectric conversion layer30may be controlled by the very-thin inorganic nanolayer40and may be, in some example embodiments, a combined work function of the first electrode10and the inorganic nanolayer40.

In some example embodiments, the effective work function on the surface of the first electrode10facing the photoelectric conversion layer30may be different from the work function of the conductor (e.g., the transparent conductor or the reflective conductor) of the first electrode10based on the influences of the inorganic nanolayer40. In some example embodiments, the effective work function on the surface of the first electrode10facing the photoelectric conversion layer30may be less than the work function of the conductor (e.g., the transparent conductor or the reflective conductor) of the first electrode10. The effective work function on the surface of the first electrode10facing the photoelectric conversion layer30may be the same as the work function of the inorganic nanolayer40or may be a medium value between the work function of the inorganic nanolayer40and the work function of the first electrode10.

In some example embodiments, the work function of the conductor (e.g., transparent conductor or reflective conductor) of the first electrode10may be greater than or equal to about 4.5 eV and an effective work function on (“at”) the surface of the first electrode10may be less than or equal to about 4.0 eV. In some example embodiments, the work function of the conductor (e.g., transparent conductor or reflective conductor) of the first electrode10may be greater than or equal to about 4.5 eV and the effective work function on (“at”) the surface of the first electrode10may be less than or equal to about 3.5 eV. In some example embodiments, the work function of the conductor (e.g., the transparent conductor or the reflective conductor) of the first electrode10may be greater than or equal to about 4.5 eV, the effective work function on (“at”) the surface10sof the first electrode10facing the photoelectric conversion layer30may be less than or equal to about 3.0 eV. In some example embodiments, the work function of the conductor (e.g., transparent conductor or reflective conductor) of the first electrode10may be greater than or equal to about 4.5 eV and the effective work function on (“at”) the surface of the first electrode10may be less than or equal to about 2.8 eV. In some example embodiments, the work function of the conductor (e.g., transparent conductor or reflective conductor) of the first electrode10may be about 4.5 eV to about 5.0 eV and the effective work function on (“at”) the surface of the first electrode10may be about 1.5 eV to about 4.0 eV, about 1.5 eV to about 3.5 eV, about 1.5 eV to about 3.0 eV, or about 1.5 eV to about 2.8 eV.

By lowering the work function on (“at”) the surface of the first electrode10facing the photoelectric conversion layer30as described above, extraction of charges (e.g., electrons) from the photoelectric conversion layer30and moving to the first electrode10may be further facilitated, and remaining charge carriers may be further reduced to show higher charge extraction efficiency, thereby improving the performance of the photoelectric conversion device100.

The photoelectric conversion device100may further include an anti-reflection layer (not shown) on one surface of the first electrode10or the second electrode20. The anti-reflection layer is disposed at a light incidence side and lowers reflectance of light of incident light and thereby light absorbance is further improved, thereby improving performance of an organic complementary metal-oxide-semiconductor (CMOS) image sensor that includes the photoelectric conversion device100. In some example embodiments, when light is incident to the first electrode10, the anti-reflection layer may be disposed on one surface of the first electrode10, and when light is incident to the second electrode20, anti-reflection layer may be disposed on one surface of the second electrode20.

The anti-reflection layer may include, for example a material having a refractive index of about 1.6 to about 2.5 and may include for example at least one of metal oxide, metal sulfide, and an organic material having a refractive index within the ranges. The anti-reflection layer may include, for example a metal oxide such as aluminum-containing oxide, molybdenum-containing oxide, tungsten-containing oxide, vanadium-containing oxide, rhenium-containing oxide, niobium-containing oxide, tantalum-containing oxide, titanium-containing oxide, nickel-containing oxide, copper-containing oxide, cobalt-containing oxide, manganese-containing oxide, chromium-containing oxide, tellurium-containing oxide, or a combination thereof; metal sulfide such as zinc sulfide; or an organic material such as an amine derivative, but is not limited thereto.

In the photoelectric conversion device100, when light enters from the first electrode10or the second electrode20and the photoelectric conversion layer30absorbs light in a particular (or, alternatively, predetermined) wavelength spectrum of light, excitons may be produced thereinside. The excitons are separated into holes and electrons in the photoelectric conversion layer30, and the separated holes are transported to an anode that is one of the first electrode10and the second electrode20and the separated electrons are transported to the cathode that is the other of the first electrode10and the second electrode20so as to flow a current.

Hereinafter, a photoelectric conversion device according to some example embodiments is described.

FIG. 2is a cross-sectional view showing a photoelectric conversion device according to some example embodiments.

Referring toFIG. 2, a photoelectric conversion device200according to some example embodiments includes a first electrode10, a second electrode20, a photoelectric conversion layer30, and an inorganic nanolayer40.

However, the photoelectric conversion device200according to some example embodiments includes a charge auxiliary layer45between the second electrode20and the photoelectric conversion layer30. The charge auxiliary layer45may enhance efficiency by facilitating movement of charges (e.g., holes) separated from the photoelectric conversion layer30.

The charge auxiliary layer45may include, for example an organic material, an inorganic material, or an organic/inorganic material. The organic material may be an organic compound having hole or electron characteristics and the inorganic material may be, for example metal oxide such as molybdenum oxide, tungsten oxide, or nickel oxide.

The charge auxiliary layer45may include for example a visible light non-absorbing material that does not absorb light in a visible region substantially, for example a visible light non-absorbing organic material.

In some example embodiments, the visible light non-absorbing material may be a compound represented by Chemical Formula 2A or 2B but is not limited thereto.

In Chemical Formula 2A or 2B,

Ar1b, Ar2b, Ar3b, and Ar4bmay independently be a substituted or unsubstituted C6 to C30 aryl group or a substituted or unsubstituted C3 to C30 heteroaryl group,

R30to R37and Rnto Rymay independently be hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heterocyclic group, a substituted or unsubstituted C1 to C6 alkoxy group, a halogen, or a cyano group.

In some example embodiments, the visible light non-absorbing material may be a compound represented by Chemical Formula 2A-1 or 2B-1, but is not limited thereto.

In Chemical Formula 2A-1 or 2B-1,

M1, M2, G2, G3, and R30to R37are the same as described above, and

R38to R45may independently be hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C1 to C6 alkoxy group, a halogen, or a cyano group.

In some example embodiments, the visible light non-absorbing material may be a compound represented by Chemical Formula 2A-1a or 2B-1 a but is not limited thereto.

In Chemical Formula 2A-1a or 2B-1a, R38to R45and Ro, and Rnare the same as described above.

The photoelectric conversion devices100and200may be applied to (“included in”) various electronic devices, for example a solar cell, an organic sensor, a photodetector, and a photosensor, but is not limited thereto.

The photoelectric conversion devices100and200may be for example applied to an organic sensor, for example an image sensor as an example of the organic sensor.

Hereinafter, an example of an image sensor including the photoelectric conversion device will be described with reference to the drawings. As an example of an image sensor, an organic CMOS image sensor is described.

FIG. 3is a cross-sectional view showing an example of an organic CMOS image sensor according to some example embodiments.

Referring toFIG. 3, an organic CMOS image sensor300according to some example embodiments includes a semiconductor substrate110, an insulation layer80, a photoelectric conversion device100, and a color filter layer70.

The semiconductor substrate110may be a silicon substrate, and is integrated with the transmission transistor (not shown) and the charge storage55. The transmission transistor and/or the charge storage55may be integrated in each pixel.

A metal wire (not shown) and a pad (not shown) are formed on the semiconductor substrate110. In order to decrease signal delay, the metal wire and pad may be made of a metal having low resistivity, for example, aluminum (Al), copper (Cu), silver (Ag), and alloys thereof, but are not limited thereto.

The insulation layer80is formed on the metal wire and the pad. The insulation layer80may be made of an inorganic insulating material such as a silicon oxide and/or a silicon nitride, or a low dielectric constant (low K) material such as SiC, SiCOH, SiCO, and SiOF. The insulation layer80has a trench85exposing the charge storage55. The trench85may be filled with fillers.

The photoelectric conversion device100is formed on the insulation layer80. The photoelectric conversion device100includes a first electrode10, an inorganic nanolayer40, a photoelectric conversion layer30, and a second electrode20as described above. Details thereof are the same as described above.

A color filter layer70is formed on the photoelectric conversion device100. The color filter layer70includes a blue filter70aformed in a blue pixel, a red filter70bformed in a red pixel, and a green filter70cformed in a green pixel. However, the color filter layer70may include a cyan filter, a magenta filter, and/or a yellow filter instead of the above color filters or may further include them in addition to the above color filters. It will be understood that a color filter is configured to selectively transmit a particular wavelength spectrum of light. Where a color filter overlaps a photo-sensing device, the color filter may be configured to selectively transmit a particular wavelength spectrum of light to a photo-sensing device so that the photo-sensing device is configured to absorb, and convert into electrical signals, the particular wavelength spectrum of light.

Focusing lens (not shown) may be further formed on the color filter layer70. The focusing lens may control a direction of incident light and gather the light in one region. The focusing lens may have a shape of, for example, a cylinder or a hemisphere, but is not limited thereto.

Even though the structure including the stacked photoelectric conversion device100ofFIG. 1is for example illustrated inFIG. 3, structures in which the photoelectric conversion device200ofFIG. 2are stacked may be applied in the same manner.

FIG. 4is a cross-sectional view showing another example of an organic CMOS image sensor according to some example embodiments.

Referring toFIG. 4, an organic CMOS image sensor400according to some example embodiments includes a semiconductor substrate110integrated with a transmission transistor (not shown) and a charge storage55, an insulation layer80, a photoelectric conversion device100, and a color filter layer70.

However, in the organic CMOS image sensor400according to some example embodiments, the positions of the first electrode10and the second electrode20of the photoelectric conversion device100are changed. That is, the first electrode10may be a light-receiving electrode.

Even though the structure including the stacked photoelectric conversion device100ofFIG. 1is for example illustrated inFIG. 6, structures in which the photoelectric conversion device200ofFIG. 2are stacked may be applied in the same manner.

FIG. 5is a schematic top plan view of an organic CMOS image sensor according to some example embodiments andFIG. 6is a cross-sectional view showing one example of the organic CMOS image sensor ofFIG. 5.

Referring toFIGS. 5 and 6, an organic CMOS image sensor500according to some example embodiments includes a semiconductor substrate110integrated with photo-sensing devices50aand50b, a transmission transistor (not shown), and a charge storage55, a lower insulation layer60, a color filter layer70, an upper insulation layer80, and a photoelectric conversion device100.

The semiconductor substrate110may be a silicon substrate and is integrated with the photo-sensing devices50aand50b, the transmission transistor (not shown), and the charge storage55. The photo-sensing devices50aand50bmay be photodiodes.

The photo-sensing devices50aand50b, the transmission transistor, and/or the charge storage55may be integrated in each pixel, and as shown in the drawing, the photo-sensing devices50aand50bmay be respectively included in a blue pixel and a red pixel and the charge storage55may be included in a green pixel.

The photo-sensing devices50aand50bsense light, the information sensed by the photo-sensing devices may be transferred by the transmission transistor, the charge storage55is electrically connected to the photoelectric conversion device100that will be described later, and the information of the charge storage55may be transferred by the transmission transistor.

A metal wire (not shown) and a pad (not shown) are formed on the semiconductor substrate110. In order to decrease signal delay, the metal wire and pad may be made of a metal having low resistivity, for example, aluminum (Al), copper (Cu), silver (Ag), and alloys thereof, but are not limited thereto. However, it is not limited to the structure, and the metal wire and pad may be disposed under the photo-sensing devices50aand50b.

The lower insulation layer60is formed on the metal wire and the pad. The lower insulation layer60may be made of an inorganic insulating material such as a silicon oxide and/or a silicon nitride, or a low dielectric constant (low K) material such as SiC, SiCOH, SiCO, and SiOF. The lower insulation layer60has a trench exposing the charge storage55. The trench may be filled with fillers.

A color filter layer70is formed on the lower insulation layer60. The color filter layer70includes a blue filter70aformed in a blue pixel and a red filter70bformed in a red pixel. In some example embodiments, a green filter is not included, but a green filter may be further included.

The upper insulation layer80is formed on the color filter layer70. The upper insulation layer80may eliminate a step caused by the color filter layer70and smoothen the surface. The upper insulation layer80and the lower insulation layer60may include a contact hole (not shown) exposing a pad, and a through-hole85(“trench”) exposing the charge storage55of the green pixel.

The photoelectric conversion device100is formed on the upper insulation layer80. The photoelectric conversion device100includes the first electrode10, the inorganic nanolayer40, the photoelectric conversion layer30, and the second electrode20as described above. Details are the same as described above.

Focusing lens (not shown) may be further formed on the photoelectric conversion device100. The focusing lens may control a direction of incident light and gather the light in one region. The focusing lens may have a shape of, for example, a cylinder or a hemisphere, but is not limited thereto.

Even though the structure including the stacked photoelectric conversion device100ofFIG. 1is for example illustrated inFIG. 6, a structure in which the photoelectric conversion device200ofFIG. 2is stacked may be applied in the same manner.

FIG. 7is a cross-sectional view showing another example of an organic CMOS image sensor.

Referring toFIG. 7, the organic CMOS image sensor600according to some example embodiments includes a semiconductor substrate110integrated with photo-sensing devices50aand50b, a transmission transistor (not shown), and a charge storage55, a lower insulation layer60, a color filter layer70, an upper insulation layer80, and a photoelectric conversion device100.

However, in the organic CMOS image sensor600according to some example embodiments, the positions of the first electrode10and the second electrode20are changed. That is, the first electrode10may be a light-receiving electrode.

Even though the structure including the stacked photoelectric conversion device100ofFIG. 1is for example illustrated inFIG. 7, a structure in which the photoelectric conversion device200ofFIG. 2is stacked may be applied in the same manner.

FIG. 8is a cross-sectional view showing another example of an organic CMOS image sensor.

An organic CMOS image sensor700according to some example embodiments includes a semiconductor substrate110integrated with photo-sensing devices50aand50b, a transmission transistor (not shown), and a charge storage55, an upper insulation layer80having a through-hole85, and a photoelectric conversion device100.

However, in the organic CMOS image sensor700according to some example embodiments, the photo-sensing devices50aand50bare stacked in a vertical direction and the color filter layer70is omitted. The photo-sensing devices50aand50bare electrically connected to charge storage (not shown) and may be transferred by the transmission transistor. The photo-sensing devices50aand50bmay selectively absorb light in each wavelength spectrum of light depending on a stack depth.

Even though the structure including the stacked photoelectric conversion device100ofFIG. 1is for example illustrated inFIG. 8, a structure in which the photoelectric conversion device200ofFIG. 2is stacked may be applied in the same manner.

FIG. 9is a cross-sectional view showing another example of an organic CMOS image sensor.

Referring toFIG. 9, an organic CMOS image sensor800according to some example embodiments includes a semiconductor substrate110integrated with photo-sensing devices50aand50b, a transmission transistor (not shown), and a charge storage55, an upper insulation layer80having a through-hole85, and a photoelectric conversion device100. However, in the organic CMOS image sensor800according to some example embodiments, the positions of the first electrode10and the second electrode20are changed. That is, the first electrode10may be a light-receiving electrode.

Even though the structure including the stacked photoelectric conversion device100ofFIG. 1is for example illustrated inFIG. 9, a structure in which the photoelectric conversion device200ofFIG. 2is stacked may be applied in the same manner.

FIG. 10is a schematic top plan view of an organic CMOS image sensor according to some example embodiments andFIG. 11is a cross-sectional view of the organic CMOS image sensor ofFIG. 10.

An organic CMOS image sensor900according to some example embodiments has a structure in which a green photoelectric conversion device selectively absorbing light in a green wavelength spectrum of light, a blue photoelectric conversion device selectively absorbing light in a blue wavelength spectrum of light, and a red photoelectric conversion device selectively absorbing light in a red wavelength spectrum of light are stacked.

The organic CMOS image sensor900according to some example embodiments includes a semiconductor substrate110, a lower insulation layer60, an intermediate insulation layer65, an upper insulation layer80, a first photoelectric conversion device100a, a second photoelectric conversion device100b, and a third photoelectric conversion device100c.

The semiconductor substrate110may be a silicon substrate and is integrated with the transmission transistor (not shown) and the charge storage55a,55b, and55c.

A metal wire (not shown) and a pad (not shown) are formed on the semiconductor substrate110, and the lower insulation layer60is formed on the metal wire and the pad.

The first photoelectric conversion device100ais formed on the lower insulation layer60.

The first photoelectric conversion device100aincludes a first electrode10aand a second electrode20afacing each other, and a photoelectric conversion layer30aand an inorganic nanolayer40adisposed between the first electrode10aand the second electrode20a. The first electrode10a, the second electrode20a, the photoelectric conversion layer30, and the inorganic nanolayer40aare the same as described above, and the photoelectric conversion layer30amay selectively absorb light in one of red, blue, and green wavelength spectra of light. In some example embodiments, the first photoelectric conversion device100amay be a red photoelectric conversion device.

The intermediate insulation layer65may be formed on the first photoelectric conversion device100a.

The second photoelectric conversion device100bmay be formed on the intermediate insulation layer65.

The second photoelectric conversion device100bincludes a first electrode10band a second electrode20b, and a photoelectric conversion layer30band an inorganic nanolayer40bbetween the first electrode10band the second electrode20b. The first electrode10b, the second electrode20b, the photoelectric conversion layer30b, and the inorganic nanolayer40bare the same as described above, and the photoelectric conversion layer30bmay selectively absorb light in one of red, blue, and green wavelength spectra of light. In some example embodiments, the first photoelectric conversion device100bmay be a blue photoelectric conversion device.

The upper insulation layer80may be formed on the second photoelectric conversion device100b. The lower insulation layer60, the intermediate insulation layer65, and the upper insulation layer80have a plurality of a plurality of through-holes exposing the charge storages55a,55b, and55c.

The third photoelectric conversion device100cis formed on the upper insulation layer80. The third photoelectric conversion device100cincludes a first electrode10cand a second electrode20cfacing each other, and a photoelectric conversion layer30cand an inorganic nanolayer40cdisposed between the first electrode10cand the second electrode20c. The first electrode10c, the second electrode20c, the photoelectric conversion layer30c, and the inorganic nanolayer40care the same as described above, and the photoelectric conversion layer30cmay selectively absorb light in one of red, blue, and green wavelength spectra of light. In some example embodiments, the third photoelectric conversion device100cmay be a green photoelectric conversion device and may be the photoelectric conversion device100.

Focusing lens (not shown) may be further formed on the photoelectric conversion device100c. The focusing lens may control a direction of incident light and gather the light in one region. The focusing lens may have a shape of, in some example embodiments, a cylinder or a hemisphere, but is not limited thereto.

In the drawing, even though as the first photoelectric conversion device100a, the second photoelectric conversion device100b, and the third photoelectric conversion device100c, the photoelectric conversion device100ofFIG. 1is for example illustrated, the photoelectric conversion device200ofFIG. 2may be applied in the same manner.

In the drawing, the first photoelectric conversion device100a, the second photoelectric conversion device100b, and the third photoelectric conversion device100care sequentially stacked, but the present disclosure is not limited thereto, and they may be stacked in various orders.

As described above, the first photoelectric conversion device100a, the second photoelectric conversion device100b, and the third photoelectric conversion device100care stacked, and thus the size of an image sensor may be reduced to realize a down-sized image sensor.

FIG. 12is a schematic cross-sectional view showing another example of an organic sensor according to some example embodiments.

Referring toFIG. 12, an image sensor1000according to some example embodiments includes a semiconductor substrate110, a lower insulation layer60, an intermediate insulation layer65, an upper insulation layer80, a first photoelectric conversion device100a, a second photoelectric conversion device100b, and a third photoelectric conversion device100c. However, the positions of the first electrode10and the second electrode20of the first photoelectric conversion device100a, the second photoelectric conversion device100b, and the third photoelectric conversion device100care changed. That is, the first electrode10may be a light-receiving electrode.

The photoelectric conversion device and the organic CMOS image sensor may be applied to various electronic devices, for example a mobile phone or a digital camera, but are not limited thereto.

FIG. 13is a schematic top plan view showing an example of an organic CMOS image sensor according to some example embodiments, andFIG. 14is a schematic cross-sectional view showing an example of the organic CMOS image sensor ofFIG. 13.

As shown with reference toFIGS. 13-14, an organic CMOS image sensor1100may include a photoelectric conversion device90that itself includes a plurality of photoelectric conversion devices90-1,90-2, and90-3on a semiconductor substrate110, where the plurality of photoelectric conversion devices90-1,90-2, and90-3are configured to convert different wavelength spectra of light (e.g., different ones of blue light, green light, or red light) into electric signals, respectively. As shown inFIG. 14, the separate photoelectric conversion devices90-1to90-3may be horizontally arranged on the semiconductor substrate110such that the photoelectric conversion devices90-1to90-3are partially or entirely overlapped with each other in a direction that extends in parallel with a top surface110aof the semiconductor substrate110. As shown each separate photoelectric conversion device90-1to90-3is connected to a separate charge storage55that is integrated into the semiconductor substrate110via a separate trench85.

Each photoelectric conversion device90-1to90-3of the photoelectric conversion device90may be any one of the photoelectric conversion devices100-400described herein. In some example embodiments, separate photoelectric conversion devices90-1to90-3may include different portions of a common, continuous layer that extends continuously between two or more of the photoelectric conversion devices90-1to90-3. In some example embodiments, the photoelectric conversion devices90-1to90-3may share a common first electrode10and a common second electrode20. In another example, two or more of the photoelectric conversion devices90-1to90-3may have different photoelectric conversion layers30that are configured to absorb different wavelength spectra of incident light. In another example, two or more of the photoelectric conversion devices90-1to90-3may have different configurations of inorganic nanolayers40. Other structures of organic CMOS image sensor1100may be are the same as one or more of the organic CMOS image sensors described with reference to any ofFIGS. 3-12.

FIG. 15is a schematic cross-sectional view of an organic CMOS image sensor according to some example embodiments.

Referring toFIG. 15, an organic CMOS image sensor1200may include a semiconductor substrate110and photoelectric conversion devices90-1and91that are stacked on each other so as to at least partially overlap in a direction extending perpendicular to the top surface110aof the semiconductor substrate110, and wherein at least one of the photoelectric conversion devices90-1and91further includes multiple photoelectric conversion devices90-2and90-3that are arranged so as to overlap in a direction extending parallel to the top surface110aof the semiconductor substrate110, and where the plurality of photoelectric conversion devices90-1,90-2, and90-3are configured to convert different wavelength spectra of light (e.g., different ones of blue light, green light, or red light) into electric signals, respectively. It will be understood that, in some example embodiments, photoelectric conversion device90-1includes multiple, horizontally-arranged photoelectric conversion devices configured to absorb different wavelengths spectra of light while photoelectric conversion device91is limited to a single photoelectric conversion device that is configured to absorb a single wavelength spectrum of light. In some example embodiments, including the example embodiments shown inFIG. 15, an entirety of the photoelectric conversion device91overlaps a limited portion of the photoelectric conversion device90-1in the direction extending perpendicular to the top surface110aand a remainder portion of the photoelectric conversion device90-1that is exposed by the photoelectric conversion device91is covered by insulation layer80. However, it will be understood that in some example embodiments an entirety of the photoelectric conversion device90-1overlaps a limited portion of the photoelectric conversion device91in the direction extending perpendicular to the top surface110a. Other structures of organic CMOS image sensor1200may be are the same as one or more of the organic CMOS image sensors described with reference to any ofFIGS. 3-12.

FIG. 16is a schematic cross-sectional view of an organic CMOS image sensor according to some example embodiments.

Referring toFIG. 16, an organic CMOS image sensor1300according to some example embodiments includes a semiconductor substrate110integrated with photo-sensing devices50aand50b, a transmission transistor (not shown) and a charge storage55, an intermediate insulation layer65, and a color filter layer70on the semiconductor substrate110, and a photoelectric conversion device90under the semiconductor substrate110. The photoelectric conversion device90shown inFIG. 18may be any of the example embodiments of photoelectric conversion devices described herein. As shown inFIG. 16, the photoelectric conversion device90may be on (e.g., above or beneath) the semiconductor substrate110, such that the color filter layer70is distal from the photoelectric conversion device90in relation to the photo-sensing devices50aand50b. Other structures of organic CMOS image sensor1300may be are the same as one or more of the organic CMOS image sensors described with reference to any ofFIGS. 3-12.

It will be understood that, where an organic CMOS image sensor includes a photo-sensing device and a photoelectric conversion device, the photo-sensing device and the photoelectric conversion device may be configured to absorb different, first and second wavelength spectra of light and convert said absorbed light into electric signals.

WhileFIG. 16illustrates example embodiments where color filters70a,70bof a color filter layer overlap separate, respective photo-sensing devices50a,50b, it will be understood that in some example embodiments an organic CMOS image sensor may include one or more photo-sensing devices and may omit one or more color filters70a,70boverlapping the one or more photo-sensing devices in the direction extending perpendicular to the top surface110a. Such one or more photo-sensing devices may be configured to sense light having a particular, limited wavelength spectrum of light in the absence of the light being filtered by a color filter prior to being received at the photo-sensing device. Accordingly, it will be understood that, in some example embodiments, the organic CMOS image sensors described herein according to various example embodiments may omit the color filters illustrated in said organic CMOS image sensors.

FIG. 17is a schematic diagram of an electronic device according to some example embodiments.

As shown inFIG. 17, an electronic device1700may include a processor1720, a memory1730, and an organic CMOS image sensor1740that are electrically coupled together via a bus1710. The organic CMOS image sensor1740may be an organic CMOS image sensor of any of the example embodiments as described herein, and the organic CMOS image sensor included in the organic CMOS image sensor1740may include any of the photoelectric conversion devices described herein according to any of the example embodiments of the inventive concepts. The memory1730, which may be a non-transitory computer readable medium, may store a program of instructions. The processor1720may execute the stored program of instructions to perform one or more functions. In some example embodiments, the processor1720may be configured to process electric signals generated by the organic CMOS image sensor1740. The processor1720may be configured to generate an output (e.g., an image to be displayed on a display interface) based on processing the electric signals.

Hereinafter, some example embodiments are illustrated in more detail with reference to examples. However, the present disclosure is not limited to the following examples.

A 150 nm-thick anode is formed by sputtering ITO on a glass substrate. Subsequently, on the anode, a 5 nm-thick charge auxiliary layer is formed by depositing a compound represented by Chemical Formula A. On the charge auxiliary layer, a 100 nm-thick photoelectric conversion layer is formed by codepositing a p-type semiconductor (λmax: 545 nm) represented by Chemical Formula B-1 and an n-type semiconductor, fullerene C60, in a volume ratio of 1:1. Subsequently, on the photoelectric conversion layer, a 1.5 nm-thick inorganic nanolayer is formed by thermally depositing Yb (WF: 2.6 eV). On the inorganic nanolayer, a 7 nm-thick cathode is formed by sputtering ITO (WF: 4.7 eV). On the cathode, a 50 nm-thick anti-reflection layer is formed by depositing aluminum oxide (Al2O3), and then, a glass plate is used for sealing to manufacture a photoelectric conversion device.

COMPARATIVE EXAMPLE 1

A photoelectric conversion device is manufactured according to the same method as Example 1 except that the inorganic nanolayer is not formed.

A photoelectric conversion device is manufactured according to the same method as Example 1 except that the p-type semiconductor and the n-type semiconductor are codeposited in a volume ratio of 1.2:1 to form a 90 nm-thick photoelectric conversion layer.

COMPARATIVE EXAMPLE 2

A photoelectric conversion device is manufactured according to the same method as Example 3 except that the inorganic nanolayer is not formed.

A photoelectric conversion device is manufactured according to the same method as Example 1 except that the p-type semiconductor and the n-type semiconductor are codeposited in a volume ratio of 2.5:1 to form an 80 nm-thick photoelectric conversion layer.

COMPARATIVE EXAMPLE 3

A photoelectric conversion device is manufactured according to the same method as Example 4 except that the inorganic nanolayer is not formed.

Evaluation I

Remaining electrons characteristics of the photoelectric conversion devices of Examples and Comparative Examples are evaluated.

The remaining electrons characteristics indicate an amount of charges photoelectrically-converted in one frame but not signal-treated and remain and thus read in the next frame and are evaluated by irradiating light in a wavelength spectrum of light in which a photoelectric conversion occurs into the photoelectric conversion devices according to Examples and Comparative Examples for a particular (or, alternatively, predetermined) time and then, turning the light off, and measuring a current amount per a 10−6second unit using a Keithley 2400 equipment.

The results are shown in Tables 1 to 3.

Referring to Tables 1 to 3, the photoelectric conversion devices including the inorganic nanolayer according to Examples show improved remaining electrons characteristics compared with the photoelectric conversion devices including no inorganic nanolayer according to Comparative Examples.

Evaluation II

Photoelectric conversion efficiency of the photoelectric conversion devices according to Examples and Comparative Examples is evaluated.

The photoelectric conversion efficiency (EQE) is evaluated in a wavelength spectrum of light of 400 nm to 720 nm in an Incident Photon to Current Efficiency (IPCE) method.

The results are shown in Tables 4 and 5.

Referring to Tables 4 and 5, the photoelectric conversion devices according to Examples show equivalent or improved photoelectric conversion efficiency compared with the photoelectric conversion devices according to Comparative Examples.

Evaluation III

An image sensor is designed by respectively applying the photoelectric conversion devices according to Examples and Comparative Examples, and YSNR10 of the organic CMOS image sensor is evaluated.

The YSNR10 of the organic CMOS image sensor is a luminance (unit: lux) in which a ratio of signal to noise (signal/noise) becomes 10, wherein the signal is a signal sensitivity obtained by performing a RGB raw signal calculated by a FDTD (finite difference time domain method) with a color correction step through a color correction matrix (CCM), and the noise is a noise generated when measuring the signal in the organic CMOS image sensor. The color correction step is a step of reducing a difference from the real color by image-processing the RGB raw signal obtained from the organic CMOS image sensor. As the YSNR10 has the lower value, the image characteristics are getting the better at a low luminance.

The results are shown in Table 6.

Referring to Table 6, YSNR10 of the photoelectric conversion device according to Example is lower than that of the photoelectric conversion device according to Comparative Example, and thus it may be expected that the sensitivity of the organic CMOS image sensor may be improved.