Regulating Circularly Polarized Light Detection via Polar-Phase Transition in Alternating Chiral-Achiral Cations Intercalation-Type Hybrid Perovskites.

Circularly polarized light (CPL) detection has wide applications in many fields, where the anisotropy factor (g ) is an important indicator to characterize the CPL detection performance. So far, many materials with high g have been reported, however, the exploration of the regulation of g is still in its infancy. Herein, two novel alternating chiral-achiral cations intercalation-type chiral hybrid perovskites (CHPs), named (R/S-1-phenylpropylamine)(propylamine)PbBr (1-R/S), exhibit above room-temperature (RT) polar-phase transition, which greatly regulates the g value. The g of 1-R is 0.04 in high-temperature phase chiral non-polar (P2 2 2 ) by applying 5 V bias, interestingly, with the temperature decrease, the g value in low-temperature phase chiral polar (P2 ) gradually increases (0.22@360K, 0.40@340K, 0.47@320K), and finally reaches a maximum of 0.5 at RT. Such value is not only the highest among 2D CHPs to date, but presents a 12.5-fold amplification compared with 0.04. Further, this rare phenomenon should be attributed to the built-in electric field induced by the polar photovoltaic effect, which sheds light on further obtaining CHPs with large g .