Engineering the Optical Properties of Eco-Friendly CuGaS2/ZnS and CuGaInS2/ZnS Core/Shell Quantum Dots for High-Performance Tandem Luminescent Solar Concentrators

Abstract

Herein, highly luminescent eco-friendly CuGaS2/ZnS (CGS/ZnS) and CuGaInS2/ZnS (CGIS/ZnS) core/shell quantum dots (QDs) are rationally prepared for luminescent solar concentrator (LSC) application. It is demonstrated that the optical properties of these core/shell QDs can be tailored by engineering the ZnS shell thickness, leading to large Stokes shifts and high-photoluminescence quantum yields up to 94.6%. As-synthesized core/shell QDs with optimized optical properties are employed to fabricate LSCs (5 × 5 × 0.5 cm3) using glasses as waveguides, wherein the individual CGS/ZnS and CGIS/ZnS QD-based LSCs, respectively, exhibit an optical efficiency (η opt) of ≈3.26% and 6.53% under AM1.5G illumination (100 mW cm−2). Remarkably, a tandem QDs-LSC integrated via vertical stacking of the top yellow-emitting CGS/ZnS QDs-LSC and bottom red-emitting CGIS/ZnS QDs-LSC delivers an optical efficiency (η opt) as high as 9.94%, which is, respectively, ≈3 and 1.5 times higher than the individual QDs-LSCs and is comparable to various best-reported QDs-LSCs. The results indicate that environment-benign I–III–VI2 core/shell QDs with engineered optical properties and LSC architectural design are promising to develop future cost-effective and high-performing building-integrated photovoltaics.