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

Yoo, Doheon; Choi, Min-Jae · ACS Nano · 2024

basic_science · Level V

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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<sub>1-<i>x</i></sub>Ga<sub><i>x</i></sub>P alloyed QDs exhibited a broad range of photoluminescence (PL) tunability, spanning from 535 nm (InP) to 465 nm (In<sub>0.62</sub>Ga<sub>0.38</sub>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<sub>0.62</sub>Ga<sub>0.38</sub>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.