Self‐Assembly of 2D Hybrid Double Perovskites on 3D Cs<sub>2</sub>AgBiBr<sub>6</sub> Crystals towards Ultrasensitive Detection of Weak Polarized Light
Xinyuan Zhang, Yunpeng Yao, Lishan Liang, Xinyi Niu, Jianbo Wu, Junhua Luo
Abstract
Abstract We report the self‐assembly of 2D double perovskite (BLA) 2 CsAgBiBr 7 (BLA=benzylammonium) on 3D Cs 2 AgBiBr 6 crystals, providing the first demonstration of polarization‐sensitive photodetection using lead‐free double perovskite heterocrystals (HCs). The (BLA) 2 CsAgBiBr 7 /Cs 2 AgBiBr 6 HC successfully combines the anisotropy of 2D double perovskites with the well‐defined interface provided by heterogeneous integration. Driven by the built‐in electric field in junction, photodetectors of HCs exhibit unique polarization dependence of zero‐bias photocurrent with a large anisotropy ratio up to 9, which is 6 times amplified as compared to the pristine 2D (BLA) 2 CsAgBiBr 7 . More importantly, the present devices can remain polarization‐sensitive with incident light intensity down to the nW cm −2 level. Our study on lead‐free hybrid perovskite HCs marks a step toward establishing robust material foundations for fundamental scientific investigations and the development of optoelectronic devices.