Circularly Polarized Perovskite Photodetector with Photocurrent Dissymmetry Factors of up to 1.95 Enabled by Liquid Crystal

Abstract Conventional circularly polarized light (CPL) detectors face a grand challenge with device integration and miniaturization because of the need for complex optical components. Chiral perovskites have recently emerged as interesting materials for CPL detectors that do not require additional optical elements but struggle to achieve a high photocurrent dissymmetry factor ( g Iph ). Herein, a simple and promising strategy is reported for high‐performance circularly polarized perovskite photodetectors (CP‐PPDs) with exceptionally high g Iph . The CP‐PPDs are fabricated using perovskite single crystals in combination with free‐standing cholesteric liquid crystal polymer films (P‐CLC) that empower the device to trigger an optically selective response. By tuning the photonic bandgap of the P‐CLC film, the spectral response of the CP‐PPDs is tunable over a broad range of wavelengths. The devices show detectivities of 6.8 × 10 13 and 5.1 × 10 13 Jones at 520 and 405 nm, respectively. Importantly, the PDs exhibit high g Iph factors of up to 1.95 at 520 nm, which is the highest reported to date for CP‐PPDs. Furthermore, as a proof‐of‐concept, CP‐PPD arrays are demonstrated for use in image sensing.