Wide-Bandgap CuBr Quantum Dots as Efficient Blue Emitters Synthesized under Ambient Conditions

Copper(I) bromide (CuBr), with its high excitonic binding energy, holds great potential for optical storage, display, and solid-state lighting. Yet, synthesizing its quantum dots (QDs) remains challenging and unexplored. In this work, blue-light-emitting CuBr QDs were synthesized by using the supersaturated recrystallization (SR) method at room temperature. The obtained stable and nontoxic QDs, with an average size of 3.4 nm, were characterized using TEM. Their optical properties in the weak confinement regime were investigated under 365 nm excitation and exhibited major emission peaks at 406 and 431 nm, corresponding to Z f and Z 1,2 transitions, respectively. The optical bandgap is tuned to 3.6 eV by reducing the particle size. Additionally, the PLQY of 36% and CIE color coordinates (0.1545 and 0.0536) make these blue-emitting QDs promising candidates for optoelectronic applications.