EMISSION-CONTROLLED FAPBI3−x BR _<i>x</i> PEROVSKITE QUANTUM DOTS <i>via</i> TOAB-INDUCED LIGAND ANION EXCHANGE

Lead halide perovskite quantum dots (PQDs) exhibit outstanding optoelectronic characteristics, further strengthened by quantum confinement effects that yield higher exciton binding energies, elevated photoluminescence quantum yields (PLQY), and narrow emission bandwidths. Through precise control of halide composition, mixed-halide PQDs can be tuned to emit across the entire visible spectrum. In this work, a ligand-assisted anion exchange approach employing tetraoctyl ammonium bromide (TOAB) is proposed to regulate the halide ratio in FAPbI[Formula: see text]Br x PQDs. The TOAB-mediated post-synthetic treatment enables partial substitution of iodide by bromide, leading to a pronounced blue shift in photoluminescence (PL) from 785[Formula: see text]nm to 536[Formula: see text]nm. Furthermore, TOAB-modified PQDs were incorporated into LED devices, which displayed electroluminescence (EL) emission shifting from 783[Formula: see text]nm to 630[Formula: see text]nm. These findings highlight the effectiveness of TOAB-based ligand modification in tailoring the emission behavior of PQDs, providing a versatile strategy for the design of wavelength-tunable optoelectronic devices.