High-Performance Planar Self-Driven Visible and Near-Infrared Photodetector Based on Pb-Sn Perovskite Single Crystals.

MAPbI 3 single crystals (SCs) are promising candidates for self-driven photodetectors due to their spontaneous polarization properties. However, their absorption cutoff wavelength, which is limited to 850 nm, severely hinders their further application in near-infrared photodetectors. In this work, a series of high-quality (MAPbI 3 ) x (FASnI 3 ) 1- x ( x = 0.8, 0.5 and 0.2) SCs with low defect density and wide absorption range were obtained by employing 1,4-pentanolactone as the solvent at low temperature. Typically, (MAPbI 3 ) 0.2 (FASnI 3 ) 0.8 SCs grown at 32 °C realize absorption in the UV-vis-NIR range from 200 to 1120 nm, which is superior among the absorption wavelengths reported for Pb-Sn perovskite SCs. Resultantly, by merit of the spontaneously polarized built-in electric field, for (MAPbI 3 ) 0.2 (FASnI 3 ) 0.8 SCs based self-driven photodetectors with planar symmetric electrodes exhibiting significant responsivities at 405-1064 nm, the device achieved a maximum responsiveness and detection of 0.247 A/W and 1.17 × 10 12 Jones, respectively.