Asymmetric Metal–Carboxylate Complexes for Synthesis of InGaP Alloyed Quantum Dots with Blue Emission

Abstract

Indium phosphide (InP) quantum dots (QDs) have attracted significant interest as next-generation light-emitting materials. However, the synthesis of blue-emitting InP-based QDs has lagged behind that of established green-and red-emitting InP QDs. Herein, we present a strategy to synthesize blue-emitting QDs by forming an InGaP alloy composition. The introduction of asymmetric In−carboxylate and Ga−carboxylate complexes resulted in a balanced synthetic reactivity between In−P and Ga−P, leading to the formation of InGaP alloyed QDs. The resultant In 1−x Ga x P alloyed QDs exhibited a broad range of photoluminescence (PL) tunability, spanning from 535 nm (InP) to 465 nm (In 0.62 Ga 0.38 P), depending on the In/Ga ratio used in the synthesis. In contrast, synthesis with symmetric In−carboxylate and Ga−carboxylate complexes produced a core/shell structure of InP/GaP QDs, which did not exhibit a blue shift of the PL peak with Ga addition. By employing a core/shell structure of In 0.62 Ga 0.38 P/ZnS QDs, we achieved a PL quantum yield of 42% at 475 nm. This work highlights the material-processing strategy essential for forming alloyed structures in III−V ternary systems.