Controlled Surface Ga Treatment to Suppress the Ostwald Ripening Process for InP Quantum Dots with Narrow-Bandwidth Emission

Environmentally friendly indium phosphide (InP) quantum dots (QDs) offer tunable emission from visible to infrared wavelengths, while synthesizing InP QDs with high brightness and narrow-bandwidth emission remains challenging. In this work, controlled surface Ga treatment was used to suppress the Ostwald ripening process during the synthesis of InP QDs with an enhanced optical performance. The tunable interaction of Ga with the QD surface was systematically investigated, and Ga treatment narrowed the full width at half-maximum (fwhm) of InP/ZnSeS QDs from 52 to 44 nm. Subsequent optimization of ZnS shell growth suppressed spectral broadening, while further increasing the ZnSeS interlayer thickness ultimately yielded a narrow fwhm of 46 nm and a high photoluminescence quantum yield (PLQY) of 96.15%. Improvement in color rendering index and correlated color temperature using InP-based quantum dots for white light-emitting diodes (LEDs) was demonstrated, and prototype devices exhibit an ultrahigh color rendering index of 95.6, a low correlated color temperature of 4414 K, and CIE coordinates of (0.36, 0.36). This work provides a promising way to obtain InP QDs with narrow-bandwidth emission and high brightness for future research and applications.