Green Deep-Eutectic Synthesis of Multinary Quantum Dots for Luminescent Polymeric Composites and LED Applications

Abstract

The production of a range of multinary quantum dots (QDs), including both ternary phase silver indium sulfide (AIS) and copper indium sulfide (CIS), and their quaternary alloys with zinc sulfide (ZAIS and ZCIS), using a l-menthol and lauric acid deep eutectic solvent (DES) was investigated. This novel synthetic approach relies on the hydrophobic nature of the lmenthol lauric acid DES to combine the typical reaction environment of hot-injection processes, commonly used for the production of high-quality QDs, with the highly desirable qualities of deep eutectics as green solvents. The deposition of a zinc sulfide shell was also investigated, resulting in an improvement of the photoluminescent quantum yield up to 65%.Moreover, the incorporation of multinary QDs produced in the l-menthol lauric acid DES in polymethyl methacrylate (PMMA) matrices was investigated, yielding both bulk slabs and colour-converting layers for white and monochromatic LEDs. These studies clearly demonstrate the feasibility and advantages of DES-based synthesis for the production of high-quality multinary QDs and their incorporation into luminescent polymeric composites with strong potential for photonics and energy applications.