High-efficiency luminescent solar concentrators based on Composition-tunable Eco-friendly Core/shell quantum dots

• Eco-friendly CuGaAlS/ZnS core/shell QDs were successfully synthesized. • Optical properties of QDs can be tuned by varying the copper composition. • The optimized QDs show a high PLQY of 91% with a large Stokes-shift. • High-performance and large-area QDs-based LSC device is fabricated. Luminescent solar concentrators (LSCs) fabricated using colloidal quantum dots (QDs) are considered as promising cost-effective solar collectors for future building-integrated photovoltaics (BIPV). Nevertheless, the solar-to-electricity conversion efficiency of the LSCs is commonly low due to limited quantum efficiency and large reabsorption loss of QDs. In addition, most of the efficient LSCs contain heavy metal-based QDs, limiting their potential commercial applications. Herein, we demonstrate a novel type of eco-friendly CuGaAlS/ZnS (CGAS/ZnS) core/shell QDs with efficient surface passivation and manipulated their optical properties by varying the copper contents, which effectively regulates the intrinsic band structure and radiative recombination dynamics. As a result, the optimal Cu-deficient CGAS/ZnS core/shell QDs exhibit the highest photoluminescence quantum yield (PLQY) of ∼91% and large Stokes shift (∼0.81 eV). The prepared QDs were applied as emitters and integrated in polymer matrix to fabricate LSCs (10×10×0.15 cm 3 ), delivering an unprecedented power conversion efficiency (PCE) of 4.29% under standard one sun AM 1.5G illumination (100 mW cm -2 ). Our results imply that tuning the components of multinary environment-friendly core/shell QDs endows the feasibility to realize low-cost and high-efficiency BIPV applications.