2D Cs₂AgBiBr₆ with Boosted Light–Matter Interaction for High‐Performance Photodetectors

Abstract

Lead‐free double perovskite Cs2AgBiBr6 has attracted significant research interests for optoelectronic applications because of its nontoxicity, inherent stability, and high detection sensitivity. In this work, the 2D Cs2AgBiBr6 with a thickness of ≈5 nm and lateral length larger than 50 µm is successfully fabricated by a space‐confined method. The fabricated ultra‐thin 2D Cs2AgBiBr6 exhibits significant advantages on photodetection, due to its enhanced light–matter interaction. Remarkably, compared with bulk Cs2AgBiBr6, 2D Cs2AgBiBr6‐based photodetectors exhibit dramatically improved optoelectronic properties including ultra‐high detectivity (D*) of 7.4 × 1014 Jones (more than ten times), photoresponsivity (R) of 54.6 A W−1 (exceeding 4.7 times), an on/off ratio of 7.4 × 104 (more than ten times), and a fast response time of ≈1.7 ms (exceeding 30 times). In addition, due to the strong photon recycling effect of Cs2AgBiBr6, optical properties in both light absorption and emission can be effectively engineered by the material thickness, which enables a tunable wavelength‐dependent photodetection. The results provide further insights on the light–matter interaction of environmentally friendly 2D perovskites related materials and shine light on their high‐performance optoelectrical applications.

Lead‐Free Double Perovskite Cs2AgBiBr6: Fundamentals, Applications, and Perspectives

“…The nanoflakes exhibits significantly enhanced light-matter interaction and thus enables high-performance photodetection with an R of 54.6 A W −1 and a remarkable D* of 7.4 × 10 14 Jones. [143] Table 1 summarizes the key parameters of Cs 2 AgBiBr 6 photodetectors together with representative lead-based/leadfree photo detectors. [144,145] Cs 2 AgBiBr 6 has shown a decent performance with a wide range photoresponse (265-620 nm), a maximum R of 54.6 A W −1 , a maximum D* of 7.4 × 10 14 Jones, a maximum LDR of 193 dB with a detecting limit of tens of pW cm −2 and the shortest response time of 17 ns, which is very promising for light detection and imaging.…”

A Study to Improve the Performance of Mixed Cation–Halide Perovskite-Based UVC Photodetectors

“…A photodetector is a device that converts an optical signal into an electrical signal and exhibits a high detection rate, allowing the detection of weak optical signals [ 1 , 2 ]. Photodetectors have been used in various fields, such as optical communication, image detection, and environmental monitoring [ 3 , 4 , 5 , 6 ]. In particular, ultraviolet C (UVC) photodetectors operating in the 280–100 nm region have been intensively studied owing to their ability to precisely detect weak signals [ 7 ].…”

Controllable volatile-to-nonvolatile memristive switching in single-crystal lead-free double perovskite with ultralow switching electric field

“…Single-crystal Cs 2 AgBiBr 6 nanoflakes were produced on the sapphire (0001) substrate by a simple space-confined method according to a previous report [29]. The AFM image in Fig.…”