Bias‐Modulated Multicolor Discrimination Enabled by an Organic–Inorganic Hybrid Perovskite Photodetector with a p‐i‐n‐i‐p Configuration

Abstract

Despite significant progress in color discrimination in various optoelectronic systems, most conventional technologies equipped with dissipative optical filters still suffer from high incident light loss and costly manufacturing. Herein, it is demonstrated that a novel class of organic-inorganic hybrid perovskite photodetectors based on a p-in -i-p structure can exhibit a switchable spectral response caused by bias modulation. A single photodetector with a p-in -i-p structure in which a low-band n-i-p perovskite diode is vertically stacked on top of a high-band p-in perovskite diode allows selective charge extraction from each perovskite diode by switching the bias polarity, resulting in fine discrimination of monochromatic red (R), green (G), and blue (B) light. Furthermore, a combination of two p-in -i-p photodetectors is successfully applied for identifying an arbitrary nonmonochromatic color (i.e., a mixed color in RGB space); thus, this approach can pave the way for developing spatially efficient and optical filter-free imaging systems. Photodetectors that convert incoming photons into electrical signals (i.e., a current) are key sensing devices in many current and emerging technologies, including imaging, optical communication, biosensing, and environmental monitoring systems. [1,2] General building blocks in photodetection systems include broadband photoactive materials and dissipative optical filters for estimating not only the brightness of illuminated light but also its spectral information.

Perovskite multifunctional logic gates via bipolar photoresponse of single photodetector

“…The perovskite layers were prepared by a two-step method: (i) vapor-phase thermal evaporation of a metal halide film (PbI 2 for MAPbI 3 and PbI 2 /SnI 2 for FA 0.5 MA 0.5 Pb 0.4 Sn 0.6 I 3 ); and (ii) conversion step to form the perovskite phase (see more details in "Methods"). The metal halide films formed by the two-step method were so resistive to solvent infiltration that the underlying layers were not chemically damaged, as reported in previous studies 36,37 . The ratio between organic and metallic cations (FA + (formamidinium):MA + (methylammonium) ≈ 1:1 and Pb 2+ :Sn 2+ ≈ 4:6) for the low-band NIR-Perov was optimally determined to have high film crystallinity, efficient device performance, and narrow bandgap (Supplementary Fig.…”

Beyond Tristimulus Color Vision with Perovskite-Based Multispectral Sensors

“…Hence, the photocurrent is determined by the photogenerated charges collected by the bottom diode. A perovskite sensor using such anti serial connected diodes has been demonstrated by Kim et al 47 The authors applied the concept to build a two-color sensor. Here, we expanded the concept to a six-channel sensor.…”

“…Schematic cross sections of the three-channel and six-channel VS color sensor devices are shown in Figure a,b, respectively. The three-channel sensor consists of three stacked photodiodes or p–i–n structures, while the six-channel sensor consists of three stacked anti serial connected diodes or p–i–n–i–p structures. , The three stacked anti serial diodes form a total of six diodes. Each of the three-channel diodes and the six-channel sensor consists of a perovskite semiconductor placed between two metal oxide layers to form a heterojunction.…”

Thermal lensing: outside of the lasing medium

“…lens). Later Kim et al [170] have developed a steadystate model of the thermal lens formed in a cylindrical solid optical element with a cylindrical heat sink around the optical element. They assumed known radiative and active cooling heat transfer rates of the cylinder (through the sink) and provided an analytical formula for the thermal lens focal length, for arbitrary absorption coefficient, including highly absorbing materials.…”