Ultrasensitive and Fast All-Inorganic Perovskite-Based Photodetector via Fast Carrier Diffusion

5 years ago

Ultrasensitive and Fast All-Inorganic Perovskite-Based Photodetector via Fast Carrier Diffusion

Keli Han, Weiqiao Deng, Junsheng Chen, Fengying Zhang, Songqiu Yang, Bin Yang, Tõnu Pullerits, Xusheng Xia

Low trap-state density, high carrier mobility, and efficient charge carrier collection are key parameters for photodetectors with high sensitivity and fast response time. This study demonstrates a simple solution growth method to prepare CsPbBr3 microcrystals (MCs) with low trap-state density. Time-dependent photoluminescence study with one-photon excitation (OPE) and two-photon excitation (TPE) indicates that CsPbBr3 MCs exhibit fast carrier diffusion with carrier mobility over 100 cm2 V−1 S−1. Furthermore, CsPbBr3 MC-based photodetectors with high charge carriers' collection efficiency are fabricated. Such photodetectors show ultrahigh responsivity (R) up to 6 × 104 A W−1 with OPE and high R up to 6 A W−1 with TPE. The R for OPE is over one order of magnitude higher (the R for TPE is three orders of magnitude higher) than that of previously reported all-inorganic perovskite-based photodetectors. Moreover, the photodetectors exhibit fast response time of ≈1 ms, which corresponds to a gain ≈105 and a gain- bandwidth product of 108 Hz for OPE (a gain ≈103 and a gain-bandwidth product of 106 Hz for TPE). CsPbBr3 microcrystal (MC)-based photodetectors exhibit ultrahigh responsivity (R) up to 6 × 104 A W−1 with one-photon excitation and R = 6 A W−1 with two-photon excitation. The photodetectors also exhibit fast response time of ≈1 ms. The sensitive and fast photoresponse is ascribed to the large absorption coefficient, low trap-state density, and high carrier mobility of CsPbBr3 MCs.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/adma.201703758