Applications of Lead-Free Cs2AgBiBr6 Single Crystals in Photodetectors and Self-Powered Photodetectors by Symmetric/Asymmetric Electrodes

Lead halide hybrid perovskites have been intensively explored as light-harvesting materials owing to their unique optoelectrical characteristics and simple deposition method. However, the toxicity and instability problems are still hindering their further development and applications. Herein, stable lead-free double perovskite Cs2AgBiBr6 single crystals (SCs) with outstanding photoelectric properties are prepared. When symmetric Au electrodes are used, the resulting photodetectors (PDs) can have broad spectral response, high responsivity of 4.88 A W-1, external quantum efficiency of 1100%, and detectivity of 1.22 x 10(13) Jones, respectively. More interestingly, when asymmetric electrodes (Au and Ag) are used, the authors obtain the first reported self-driven PD based on the lead-free perovskite SC, to the best of the authors' knowledge. The device exhibits good photoresponse properties at a bias of 0 V. Both devices hold short response time at mu s scale, which are among the best reported lead-free perovskite PDs. Both devices demonstrate decent stabilities in air without encapsulation. All results demonstrate that Cs2AgBiBr6 SCs have great potential in the application of optoelectronic devices.

Automated summary

Lead halide hybrid perovskites have been extensively studied as light-harvesting materials due to their unique optoelectrical characteristics and easy deposition method. However, toxicity and stability issues have hindered their further development. In this study, stable lead-free Cs2AgBiBr6 single crystals with excellent photoelectric properties were prepared. Symmetric Au electrodes resulted in photodetectors with broad spectral response, high responsivity, external quantum efficiency, and detectivity. Interestingly, asymmetric electrodes (Au and Ag) led to the development of the first self-driven photodetector based on the lead-free perovskite single crystals, showing good photoresponse properties at 0 V bias. Both devices demonstrated short response times at the microsecond scale and good stability without encapsulation, indicating great potential for optoelectronic device applications.