Solution‐Based Integration of Vertically Stacked Organic Photodetectors Toward Easy‐To‐Fabricate Filterless Multi‐Color Light Sensors

Abstract

Solution‐processed, color‐selective organic photodetectors are uniquely positioned to deliver high‐performance, low‐cost, multicolor light sensors/imagers beyond the limitations of conventional, color‐filter‐based technologies. To realize such potential, however, a prominent challenge has been the solution‐based, monolithic integration of vertically stacked organic photodetectors, which would enable multicolor sensing with optimum light collection while benefiting from the scalability, cost, and sustainability edges of solution‐based manufacturing. To tackle this challenge, this paper demonstrates, for the first time, the monolithic integration of vertically stacked solution‐processed organic photodetectors for independent, multicolor light sensing within the same pixel area. The solvent orthogonality challenge is tackled by selecting polymer‐based photoactive layers and an insulating polymeric spacer—for independent biasing and photocurrent readout—with compatible processing conditions. Based on the suitable characteristics of blue‐ and green‐sensitive standalone devices, the vertically stacked, monolithic device architecture is optimized by also incorporating semitransparent electrodes for photons to reach deep into the stack. The resultant device architecture enables efficient blue‐ and green‐selective photodetection with state‐of‐the‐art linearity, alongside speed of response adequate for real‐world applications. Based on its solution‐processability and modularity, this approach paves the way for the facile, solution‐based fabrication of organic imagers covering multiple spectral regions with high sensitivity and resolution.

Recent Advances in Smart Organic Sensors for Environmental Monitoring Systems

“…136 Zhao et al demonstrated the solution-based monolithic integration of vertically stacked OPDs. 137 They developed polymer-based photodetectors of F8T2:PCBM for blue color sensing and MEH-PPV:PCBM active layers for green color sensing (Figure 10a). Solution-processed poly(methyl methacrylate) was introduced as an insulating spacer between OPDs, which allowed the monolithic device to achieve independent bias and readout through the stacked photodetectors.…”

“…Zhao et al demonstrated the solution-based monolithic integration of vertically stacked OPDs . They developed polymer-based photodetectors of F8T2:PCBM for blue color sensing and MEH-PPV:PCBM active layers for green color sensing (Figure a).…”

“…(b) Optical properties of stacked OPDs. Reproduced with permission from ref . Copyright 2022, Wiley.…”

Solution-based fullerene-free route enables high-performance green-selective organic photodetectors

“…Due to their optoelectronic versatility, organic semiconductors enable narrowband photodetection through a variety of strategies, which can be grouped into three main classes: narrowband-absorption-type (NBA) [1,17,18]; filtered (including input optical filtering and internal filtering via charge collection narrowing, charge injection narrowing, or exciton dissociation); and microcavity-resonance-based [19][20][21][22]. Among these strategies, NBA photodetection has been mainstream due to its appealing trade-off between simplicity and performance, which is of fundamental importance for the realization of easy-to-make optoelectronics alternative to silicon-based technologies [6,19,23]. Specifically, an NBA photodetector consists of a sandwich-type device stack comprising a thin (∼100 nm) organic semiconductor layer, which selectively absorbs photons within the target spectral range [1,17,18] (figure 1(a)).…”

Filterless Visible‐Range Color Sensing and Wavelength‐Selective Photodetection Based on Barium/Nickel Codoped Bandgap‐Engineered Potassium Sodium Niobate Ferroelectric Ceramics

“…[6] The recent development of graphene-based, 2D, and halide perovskite photodetectors has not made much difference in terms of the dependency on applying filters or tuning the compositions of the compounds for wavelength-selective photodetection. [7][8][9][10] Therefore, filterless, wavelength-selective photodetection that can be realized on a monolithic material or single component Photosensors, photodetectors, or color sensors are key components for various optical and optoelectronic applications. Semiconductor-based photodetection has been a dominator which is excellent at measuring the photon intensity of incident light.…”