Interfacial Oxidation and Photoluminescence of InP-Based Core/Shell Quantum Dots

• Published in: Chemistry of materials Vol. 30; no. 19; pp. 6877 - 6883
• Main Authors: Tessier, Mickael D, Baquero, Edwin A, Dupont, Dorian, Grigel, Valeriia, Bladt, Eva, Bals, Sara, Coppel, Yannick, Hens, Zeger, Nayral, Céline, Delpech, Fabien
• Format: Journal Article
• Language: English
• Published: American Chemical Society 09-10-2018
• Subjects: Chemical Sciences; Coordination chemistry
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/acs.chemmater.8b03117

Indium phosphide colloidal quantum dots (QDs) are emerging as an efficient cadmium-free alternative for optoelectronic applications. Recently, syntheses based on easy-to-implement aminophosphine precursors have been developed. We show by solid-state nuclear magnetic resonance spectroscopy that this new approach allows oxide-free indium phosphide core or core/shell quantum dots to be made. Importantly, the oxide-free core/shell interface does not help in achieving higher luminescence efficiencies. We demonstrate that in the case of InP/ZnS and InP/ZnSe QDs, a more pronounced oxidation concurs with a higher photoluminescence efficiency. This study suggests that a II–VI shell on a III–V core generates an interface prone to defects. The most efficient InP/ZnS or InP/ZnSe QDs are therefore made with an oxide buffer layer between the core and the shell: it passivates these interface defects but also results in a somewhat broader emission line width.