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 CuGaS 2 /ZnS (CGS/ZnS) and CuGaInS 2 /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 cm 3 ) 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–VI 2 core/shell QDs with engineered optical properties and LSC architectural design are promising to develop future cost‐effective and high‐performing building‐integrated photovoltaics.