Modulating the birefringence of two-dimensional hybrid lead bromide perovskites by pyridine derivative cations

Birefringent crystals for modulating the polarization of light are of technological importance in optical communications. Herein we provide two novel two-dimensional hybrid halide perovskites, [(H2-dpys)(PbBr4)] (1) (dpys = di(pyridin-4-yl)sulfane) and...