Finely Controlled Circularly Polarized Luminescence with Multimode Dynamic Response of Hybrid Metal Chlorides for Circularly Polarized White Light‐Emitting Diode and Programmable Information Encryption

Stimulus‐responsive materials that exhibit efficient circularly polarized luminescence (CPL) have gained much interest for application in advanced smart photonics. Herein, the CPL‐active enantiomorphic 0D Sb 3+ ‐doped (R/S) 2 InCl 7 (R/S = R/S‐2‐methylpiperazine) are synthesized via a solution method. They show efficient broadband yellow emission with a near‐unity photoluminescence quantum yield and a CPL asymmetry factor of 1.7 × 10 −3 . Their fascinating chiroptical activity should be attributed to the chirality transfer and self‐trapped exciton emission caused by strong electron–phonon interaction. Particularly, H 2 O‐induced structural transformation is demonstrated to obtain non‐emission of Sb 3+ ‐doped (R/S) 2 InCl 7 ·H 2 O after exposure to a humid environment. Importantly, Sb 3+ ‐doped (R/S) 2 InCl 7 exhibits unique nonlinear optical responses, and the rotation angle between the quarter‐wave plate and linearly polarized plate can regulate the reversible switching of Sb 3+ ‐doped (R/S) 2 InCl 7 between yellow emission and negligible luminescence. Moreover, a circularly polarized white light‐emitting diode is fabricated by combining blue phosphors BaMgAl 10 O 17 :Eu 2+ , and the device exhibits tunable switching control of positive and warm white light by regulating the rotation angle of linear polarizer plate. Based on the tunable optical responses of Sb 3+ ‐doped (R/S) 2 InCl 7 , a programmable multi‐mode fluorescence encoding system is constructed, and four‐level information encryption and three‐level encrypted 3D color codes are also realized in a further proof‐of‐concept experiment.