CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2016-0081554 filed in the Korean Intellectual Property Office on Jun. 29, 2016, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Field

Example embodiments provide an organic photoelectronic device and an image sensor including the same.

2. Description of the Related Art

A photoelectronic device may convert light into an electrical signal using photoelectric effects. A photoelectronic device may include a photodiode, a phototransistor, etc. A photoelectronic device may be applied to (e.g., included in) various devices, including image sensors, a solar cell, an organic light emitting diode, some combination thereof, etc.

An image sensor including a photodiode requires relatively high resolution and thus a smaller pixel. At present, a silicon photodiode is widely used. In some cases, a silicon photodiode exhibits a problem of deteriorated sensitivity because of a relatively small absorption area due to relatively small pixels. Accordingly, an organic material that is capable of replacing silicon has been researched.

An organic material has a relatively high extinction coefficient and selectively absorbs light in a particular wavelength region depending on a molecular structure, and thus may simultaneously replace a photodiode and a color filter and resultantly improve sensitivity and contribute to relatively high integration.

SUMMARY

Example embodiments provide an organic photoelectronic device capable of increasing wavelength selectivity.

Example embodiments also provide an image sensor including the organic photoelectronic device.

Example embodiments also provide an electronic device including the image sensor.

According to example embodiments, an organic photoelectronic device includes a first electrode and a second electrode facing each other and a light-absorption layer between the first electrode and the second electrode and including a p-type light-absorbing material and an n-type light-absorbing material, wherein at least one of the p-type light-absorbing material and the n-type light-absorbing material selectively absorbs a part of visible light, and the light-absorption layer includes a photoelectric conversion region including the p-type light-absorbing material and the n-type light-absorbing material and a doped region including at least one of the p-type light-absorbing material and the n-type light-absorbing material, and an exciton quencher.

The photoelectric conversion region may include a first photoelectric conversion region near to the first electrode and a second photoelectric conversion region near to the second electrode, and the doped region is between the first photoelectric conversion region and the second photoelectric conversion region.

The second electrode may be nearer to light incidence side than the first electrode, and a thickness of the second photoelectric conversion region may be the same as or larger than a thickness of the first photoelectric conversion region.

The exciton quencher may include a metal, a semi-metal, a metal oxide, a semi-metal oxide, an organic material, or a combination thereof.

The exciton quencher may include a hole transportable metal, a hole transportable semi-metal, a hole transportable metal oxide, a hole transportable semi-metal oxide, a hole transportable organic material, or a combination thereof.

The exciton quencher may include copper, silver, gold, aluminum, a molybdenum oxide, a tungsten oxide, a vanadium oxide, a rhenium oxide, a nickel oxide, or a combination thereof.

The exciton quencher may be included in an amount of less than or equal to about 50 volume % based on the amount of the doped region.

At least one of the p-type light-absorbing material and the n-type light-absorbing material may selectively absorb at least one of a wavelength of greater than or equal to about 400 nm and less than 500 nm, a wavelength region of about 500 nm to about 600 nm, and a wavelength region of greater than about 600 nm and less than or equal to about 700 nm.

The light-absorption layer may absorb first visible light and second visible light that are different wavelength regions from each other, and the first visible light may be absorbed at maximum in the photoelectric conversion region and the second visible light may be absorbed at maximum in the doped region.

One of the p-type light-absorbing material and the n-type light-absorbing material may selectively absorb the first visible light and the other of the p-type light-absorbing material and the n-type light-absorbing material may absorb the first visible light and the second visible light.

The first visible light may be a wavelength region of about 500 nm to about 600 nm and the second visible light may be a wavelength of greater than or equal to about 400 nm and less than 500 nm.

External quantum efficiency of the organic photoelectronic device for the first visible light and the second visible light may satisfy Relationship Equation 1.
EQEmax/EQE450 nm≥3.80  [Relationship Equation 1]

In Relationship Equation 1,

EQEmaxis external quantum efficiency of the first visible light at a maximum absorption wavelength which is measured using an incident photon to current efficiency (IPCE), and

EQE450 nmis external quantum efficiency at 450 nm which is measured using an incident photon to current efficiency (IPCE).

The p-type light-absorbing material may selectively absorb the first visible light and the n-type light-absorbing material may absorb the first visible light and the second visible light.

The n-type light-absorbing material may be fullerene or a fullerene derivative.

The p-type light-absorbing material may be an organic material including a core structure including an electron donating moiety, a pi conjugation linking group, and an electron accepting moiety.

The p-type light-absorbing material may be a compound represented by Chemical Formula 1.



In Chemical Formula 1,

X is Se, Te, SO, SO2, or SiRaRb,

EDG is an electron donating group,

EAG is an electron accepting group, and

R1, R2, Ra, and Rbare independently hydrogen or a monovalent substituent.

The p-type light-absorbing material may be a compound represented by Chemical Formula 1 A or 1B.



In Chemical Formula 1A or 1B,

X is Se, Te, SO, SO2, or SiRaRb,

Ar is a substituted or unsubstituted 5-membered ring, a substituted or unsubstituted 6-membered ring, or a condensed ring of the two or more foregoing rings,

each of Ar1aand Ar2aare independently a substituted or unsubstituted C6to C30aryl group or a substituted or unsubstituted C3to C30heteroaryl group,

G1is selected from a single bond, —(CRgRh)n2—, —O—, —S—, —Se—, —N═, —NRi—, —SiRjRk—, and —GeRiRm—, wherein n2 is 1 or 2, and

each of R1ato R3a, Ra, and Rbare independently hydrogen, a substituted or unsubstituted C1to C30alkyl group, a substituted or unsubstituted C6to C30aryl group, a substituted or unsubstituted C3to C30heteroaryl group, a substituted or unsubstituted C1to C6alkoxy group, halogen, or a cyano group.

The p-type light-absorbing material may be a compound represented by one of Chemical Formulae 1A-1 to 1B-4.



In Chemical Formulae 1A-1 to 1B-4,

X is Se, Te, SO, SO2, or SiRaRb,

Z1is O or CRcRd,

Y1is N or CRe,

Y2is selected from O, S, Se, Te, and C(Rf)(CN),

Y3is O, S, Se, or Te,

Y4is N or NR18a,

Y5is CR19aor C═CR20a(CN),

each of Ar1aand Ar2a are independently a substituted or unsubstituted C6to C30aryl group or a substituted or unsubstituted C3to C30heteroaryl group,

each of R1ato R3a, R11a, R12a, R15ato R20a, R24a, R25a, and Rato Rfare independently hydrogen, a substituted or unsubstituted C1to C30alkyl group, a substituted or unsubstituted C6to C30aryl group, a substituted or unsubstituted C3to C30heteroaryl group, a substituted or unsubstituted C1to C6alkoxy group, a halogen, or a cyano group,

n1 is 0 or 1,

m1 is 0 or 1, and

m2 is an integer of 0 to 4.

According to example embodiments, an image sensor includes the organic photoelectronic device.

According to example embodiments, an electronic device includes the image sensor.

