Achiral phosphonium induced remarkable circular polarized luminescence in a chiral cadmium(II) halide perovskite material.

Circular polarized luminescence (CPL) sensitive two-dimensional organic inorganic halide perovskites have versatile applications in optical displays, encrypted transmission and quantum communications. Here, a new chiral hybrid [MePh 3 P] 2 CdCl 4 (PCC) single crystal (SC) is synthesized using an achiral phosphonium cation by a solvent evaporation process at room temperature (rt). SC x-ray study reveals a non-centrosymmetric point group 23, with 2 1 -screw optical axes providing a chiral Sohncke space group. Hirshfeld surface analysis suggests long-range H-bonding and ionic interactions (~ 3-9 kJ mol -1 ) and short-range Van der Waals and dispersion interactions (∼0.4-4 kJ mol -1 ). Both the PCC thin films and SCs exhibit prominent circular dichroism (CD) and remarkably superior CPL activity at rt (|g CD | ≈ 5 × 10 -3 and |g lum | ≈ 4.3 × 10 -2 ).