Physically Detachable and Operationally Stable Cs₂SnI₆ Photodetector Arrays Integrated with µ‐LEDs for Broadband Flexible Optical Systems

Abstract

With the surge in perovskite research, practical features for future applications are desired to be secured, but the reliability of the materials and the use of hazardous Pb are longstanding problems. Here, an air‐stable Cs2SnI6 (CSI) is prepared via diluted hydriodic acid solvent‐based precursor optimization during scalable hydrothermal growth. Materials characterization is performed using various elemental peak analyses and crystallographic identification. The resulting CSI exhibits long‐term operating stability over 6 months, i) at elevated temperatures, ii) in ambient air, and iii) under light illumination from UV to near‐infrared. More importantly, to demonstrate an intriguing class of applications up to system level, physically detachable CSI photodetector arrays (PD‐arrays), integrated with micro‐light‐emitting‐diodes (μ‐LEDs) arrays, are successfully fabricated. In addition, 3 × 3 flexible CSI PDs are fully operational, even in air, and their spatial uniformity in pixels is quantitatively evaluated. The charge‐transport mechanisms of the CSI PDs under light and elevated temperature are assessed via temperature‐dependent characterization from 148 to 373 K, implying the involvement of 3D variable‐range hopping. Multicycle evaluation of the CSI PD‐arrays confirms their operational stability in AC and DC modes, demonstrating this platform's potential benefit for wireless optical interconnection in advanced Si technology.

Low‐Temperature Crystallized and Flexible 1D/3D Perovskite Heterostructure with Robust Flexibility and High EQE‐Bandwidth Product

“…Our flexible photodetectors showed a high EQE-Bandwidth product of 119 kHz under −0.6 V bias. Figure 4i summarizes the EQE-Bandwidth product of reported flexible photodetectors, [60][61][62][63][64][65][66][67] and our detectors show about one order magnitude larger value under a lower bias voltage, indicating outstanding detection capability. The performance comparisons with other morphology of CsPbI 3 photodetectors and flexible photodetectors are presented in Tables S1 and S2 (Supporting Information), respectively.…”

Emerging Opportunities in Lead-Free and Lead–Tin Perovskites for Environmentally Viable Photodetector Applications

“…Variations in the crystal structure and bandgap tunability enable the use of Sn and Sn–Pb perovskites in photodetectors in the NIR, visible, and UV ranges. ,− Due to the solution and low-temperature processability, it is feasible to render flexibility, which is uncommon in traditional photodetectors that are mainly fabricated by growing inorganic semiconductor materials on a wafer using high-temperature epitaxial growth methods. Flexible photodetectors can be bent, rolled, folded, or even stretched in a variety of applications, such as wearable devices, e-skin, smart textiles, and artificial electronic eyes. ,,, Owing to the remarkable optoelectronic properties of perovskites, enhanced photodetectors can operate under low or even zero external bias in self-powered applications. Sn and Sn–Pb mixed perovskite have been successfully employed in the development of sensitive, durable, and flexible photodetectors, as depicted in Figure a …”

“…Flexible photodetectors can be bent, rolled, folded, or even stretched in a variety of applications, such as wearable devices, e-skin, smart textiles, and artificial electronic eyes. 13,109,115,159 Owing to the remarkable optoelec-tronic properties of perovskites, enhanced photodetectors can operate under low or even zero external bias in self-powered applications. Sn and Sn−Pb mixed perovskite have been successfully employed in the development of sensitive, durable, and flexible photodetectors, as depicted in Figure 10a.…”

Metal Ion-Incorporated Lead-Free Perovskites toward Broadband Photodetectors

“…(d) Detectivity and responsivity of the state-of-the-art perovskite-based photodetectors, representing the best performance for all-inorganic lead-free perovskites. Data points are obtained from refs − .…”