“Surface‐Filming Assembly” Strategy for Facilely Constructing and Adjusting Circularly Polarized Luminescence from Perovskite/Chiral Helical Polyacetylene Films

Abstract Tunable circularly polarized luminescence (CPL) has attracted substantial research interest. Till date, the main methods for adjusting CPL is by changing the ratio of fluorescent components and/or regulating external stimuli. Although these adjustment methods have been demonstrated to be reliable, most of them show disadvantages including challenging molecular design, complicated and cumbersome material fabrication, and rigorous adjustment conditions. Herein, the “Surface‐Filming Assembly” (SFA) strategy for conveniently and efficiently modulating CPL by taking the perovskite/chiral helical polyacetylene system as a model is proposed and established. This strategy can facilely achieve multicolor CPL by simply changing the color (or number) of perovskite fluorescent layers and/or the attaching order of the perovskite layers in the assembled multilayer film. Compared with previously reported methods, the SFA strategy integrates the preparation process and adjustment in one single step, simplifying the preparation process (especially the preparation of perovskite with different ratios of halogen atoms) and making adjustment simple and efficient. The SFA strategy and different CPL generation mechanisms to achieve multicolor and white‐color emission with g_lum up to 10⁻² are combined. Based on the CPL film and the solvent sensitivity of perovskite, a solvent‐responsive CPL‐emitting switch and further applied the CPL sample in multiple information displays and encryption are realized.