Work

Ultralow dark current in near-infrared perovskite photodiodes by reducing charge injection and interfacial charge generation

Year: 2021

Type: article

Abstract: Metal halide perovskite photodiodes (PPDs) offer high responsivity and broad spectral sensitivity, making them attractive for low-cost visible and near-infrared sensing. A significant challenge in achieving high detectivity in PPDs is lowering the dark current density ( J D ) and noise current ( i n ). This is commonly accomplished using charge-blocking layers to reduce charge injection. By analyzing the temperature dependence of J D for lead-tin based PPDs with different bandgaps and electron-blocking layers (EBL), we demonstrate that while EBLs eliminate electron injection, they facilitate undesired thermal charge generation at the EBL-perovskite interface. The interfacial energy offset between the EBL and the perovskite determines the magnitude and activation energy of J D . By increasing this offset we realized a PPD with ultralow J D and i n of 5 × 10 −8 mA cm −2 and 2 × 10 −14 A Hz −1/2 , respectively, and wavelength sensitivity up to 1050 nm, establishing a new design principle to maximize detectivity in perovskite photodiodes.

Source: Nature Communications

DOI: 10.1038/s41467-021-27565-1