Blue Light Emission and Stable Zero-Dimensional Hybrid Zinc Halide Modulated by Donor-π-Acceptor-Based Organic Cation

Abstract Zero-dimensional organic–inorganic hybrid zinc halides have emerged as promising lead-free candidates for blue-emitting optoelectronic devices due to their structurally tunable nature; however, their practical application is severely hindered by inherent optical inertness and unsatisfactory luminescence efficiency. Herein, a novel donor-π-acceptor (D-π-A) organic cation, 7-chloro-N-[2-(dimethylamino)ethyl]quinolin-4-amine (CDQI), is rationally designed, and a zero-dimensional (0D) hybrid zinc halide crystal (CDQI)(ZnCl4)·H2O is prepared via a facile solvothermal method. Notably, the crystal exhibits efficient broadband blue emission centered at 450 nm with a high photoluminescence quantum yield (PLQY) of 51.73%. Benefiting from the synergistic effect of hydrogen bonds and aromatic π–π stacking and the electronic transfer effect of the D-π-A structure, it also possesses excellent structural and optical stability in harsh environments. The assembled light-emitting diode achieves standard white-light emission with CIE coordinates of (0.31, 0.32) and a high color rendering index (CRI) of 92.8, long-term, stable luminescence, and linear, power-dependent emission. This work proposes an efficient D-π-A cation modulation strategy, offering a reliable guideline for developing high-performance lead-free blue-emitting hybrid halide optoelectronic materials.