One-Pot Gram-Scale, Eco-Friendly, and Cost-Effective Synthesis of CuGaS2/ZnS Nanocrystals as Efficient UV-Harvesting Down-Converter for Photovoltaics

Abstract

It is presented for the first time nontoxic CuGaS2/ZnS quantum dots (QDs) with free-self-reabsorption losses and large Stokes shift (>190 nm) synthesized on an industrially gram-scale as an alternative for Cd-based energy-downshift (EDS)-QD layers. The QDs exhibit a typical EDS that absorbs only UV light (<407 nm) and emits the whole range of visible light (400-800 nm) with a high photoluminescence-quantum yield of approximate to 76%. The straightforward application of these EDS-QDs on the front surface of a monocrystalline p-type silicon solar cell significantly enhances the short-circuit current density by approximate to 1.64 mA cm(-2) (+4.20%); thereby, improving the power-conversion-efficiency by approximate to 4.11%. The significant improvement in the external quantum efficiency increases by approximate to 35.7% and that in the surface reflectance decreases by approximate to 14.1% in the UV region (300-450 nm) clearly manifest the photovoltaic enhancement. Such promising results together with the simple (one-pot core/shell synthesis), cost-effective (reduction in a bill of material-system by approximate to 2.62%), and scalable (2000 mL three-neck flask, 11 g of QDs) preparation process might encourage the manufacturers of solar cells and other optoelectronic applications to apply these EDS-QDs to different broader eco-friendly applications.