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.

Automated summary

In this study, highly luminescent CuGaS2/ZnS and CuGaInS2/ZnS core/shell quantum dots (QDs) were prepared for luminescent solar concentrator (LSC) application. The optical properties of the QDs were tailored by adjusting the ZnS shell thickness. LSC devices fabricated using the optimized QDs exhibited high optical efficiency, and a tandem QDs-LSC structure achieved a significantly improved optical efficiency compared to individual QDs-LSCs.