Solution-processed MAPbI3/Cs2AgBiBr6 heterostructure through epitaxial growth for broadband photo-detection

All-inorganic halide semiconductors with perovskite or perovskite-like structure have aroused a widespread concern recently for its environmental friendliness and stabilities while possessing excellent optoelectronic properties. Double perovskite Cs 2 AgBiBr 6 single crystal (SC) is one of the most representative materials in the latest research area. To further improve the device response range and decrease its dark current density effectively, functional layers based on the solution-processed epitaxial method are normally fabricated as heterojunctions. Herein, a novel idea of a broadband heterojunction MAPbI 3 (MA = CH 3 NH 3 )/Cs 2 AgBiBr 6 is proposed in this work to achieve this goal. A MAPbI 3 layer is fabricated on Cs 2 AgBiBr 6 SC substrates through immersing Cs 2 AgBiBr 6 SC into MAPbI 3 solution at a MAPbI 3 crystallization temperature. Ultimately, this heterojunction device expands the absorption limit from 618 to 838 nm, makes responsivity range redshift from 629 to 860 nm, and achieves a responsivity of 16.8 mA W −1 while the detectivity of 1.33 × 10 11 Jones under 622 nm 0.55 mW cm −2 illumination at −20 V bias, maintaining excellent optoelectronic properties.