Narrow-Band Organic Photodiodes for High-Resolution Imaging

Abstract

There are growing opportunities and demands for image sensors that produce higher-resolution images, even in low-light conditions. Increasing the light input areas through 3D architecture within the same pixel size can be an effective solution to address this issue. Organic photodiodes (OPDs) that possess wavelength selectivity can allow for advancements in this regard. Here, we report on novel push-pull D-π-A dyes specially designed for Gaussian-shaped, narrow-band absorption and the high photoelectric conversion. These p-type organic dyes work both as a color filter and as a source of photocurrents with linear and fast light responses, high sensitivity, and excellent stability, when combined with C60 to form bulk heterojunctions (BHJs). The effectiveness of the OPD composed of the active color filter was demonstrated by obtaining a full-color image using a camera that contained an organic/Si hybrid complementary metal-oxide-semiconductor (CMOS) color image sensor.

Efficiency and spectral performance of narrowband organic and perovskite photodetectors: a cross-sectional review

“…These values are fully compatible with applications such as colour imaging for consumer electronic devices, as well as more demanding applications, e.g., computer vision. Particularly successful implementations have relied on dedicated molecular design strategies, e.g., D-A molecules approaching the cyanine limit (FWHM EQE ≈90-100 nm) [120,126]. Additionally, two important schemes relating to aggregation effects in the solid state have emerged as highly effective for achieving NBA-type photodetection with EQE widths well below 100 nm.…”

“…Chloroboron subphthalocyanine (SubPc) is another small molecule that has delivered high phototransduction efficiency in a number of works, giving an EQE p of 62.6% in combination with DCV3T [58], and 60.1% in combination with quinacridone [58,61] (figure 7(b)). Newly synthesised small-molecule donors featuring a D-A structure approaching the cyanine limit have also yielded EQE values in the ≈50%-70% range in combination with fullerenes ( figure 7(b)) [120,126,128,129]. Finally, Li et al demonstrated the potential of a singlecomponent squaraine photoactive layer, achieving an EQE p as high as 66% [72].…”

“…A considerable number of NBA-type devices feature a FWHM EQE greater than 100 nm. A recurrent feature of many of them is the use of fullerenes, which generally broaden the spectral width and/or reduce the spectral rejection ratio (e.g., with respect to the blue, see figure 7(b)) [120,125,126,128,129]. A number of fullerene-free strategies have thus been considered to overcome this challenge and achieve FWHM EQE values around or below 100 nm.…”

Polymer:Fullerene Bimolecular Crystals for Near‐Infrared Spectroscopic Photodetectors

“…Solution processable organic bulk‐heterojunctions (BHJs) or metal‐halide perovskites are in this respect interesting candidates, and several approaches to achieve wavelength‐selective photodetection using these materials have been recently proposed . For photoactive materials with tailored absorption spectra, high responsivities were achieved in the short‐wavelength regime (<700 nm), with a spectral full‐width at half‐maximum (FWHM) of the order of 100 nm . Narrower spectral responses were recently demonstrated through the use of thick active layers, resulting in carrier collection only for weakly absorbed wavelengths at the optical gap …”

Systematic Optical Design of Constituting Layers to Realize High‐Performance Red‐Selective Thin‐Film Organic Photodiodes

“…Over the past several years, extensive research on OPDs with color selectivity has been carried out. Most of this research, however, has focused on green‐ or blue‐selective OPDs, presumably because of the difficulties related to realizing red‐selective absorption of organic semiconductors. To expand the absorption spectrum of π‐conjugated organic compounds to 600 nm or higher, a largely delocalized conjugation structure should be introduced into the molecular structure.…”