ESPCI web site
Friday the 6th at 11 am
Amphi Charpack
Heavy-Metal Free III-V QDs : From Structural Control to Core/Shell Synthesis and Applications
Colloidal Cd-based II-VI semiconductor nanocrystals (NCs) have achieved high synthetic maturity, including precise control over size, crystal structure, and core-shell interfaces, enabling their commercial use in displays. However, the toxicity of Cd limits their broader application. As an alternative, heavy-metal-free III-V semiconductor nanocrystals such as InP and InAs comply with RoHS regulations, but their synthesis and property control remain much less advanced. In this talk, I will present the synthesis of wurtzite InP NCs using a cation exchange method, demonstrating tunable fluorescence through size control. This method is also extended to wurtzite-phase InAs NCs and shows potential for GaAs NC synthesis. Furthermore, we develop a safer fluoride-based etchant using ZnF2 to replace hydrofluoric acid for producing high-quality InP core/shell NCs. The in situ generated fluoride ions also assist in regulating shell growth. We further investigate the surface chemistry of III-V NCs and found minimal native oxide formation during synthesis, suggesting that previously reported amorphous oxides likely result from post-synthetic treatment. Using surface ligand activation, we achieved quantum yields over 90% for III-V NCs without hydrofluoric acid etching. These advances contribute to the development of environmentally friendly III-V NCs for future optoelectronic applications.
