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

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 x 5 x 0.5 cm(3)) using glasses as waveguides, wherein the individual CGS/ZnS and CGIS/ZnS QD-based LSCs, respectively, exhibit an optical efficiency (eta(opt)) of approximate to 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 (eta(opt)) as high as 9.94%, which is, respectively, approximate to 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.