Durable Quantum Dot-Based Luminescent Solar Concentrators Enabled by a Photoactive Block Copolymer

Quantum dot (QD)-based luminescent solar concentrators (LSCs) promise to revolutionize solar energy technology by replacing building materials with energy-harvesting devices. However, QDs degrade under air, limiting the long-term performance of QD-LSCs. This study introduces an innovative approach to prevent QDs degradation by utilizing a photoactive polymer matrix (maleic anhydride-grafted poly(styrene-b-ethylene-co-butylene-b-styrene, SEBS-g-MA). This strategy has been tested outdoors over a 2-year period on five LSCs, followed by characterization of the weathered devices. The tested LSCs consist of three QD-LSCs (CuInS₂/ZnS, InP/ZnSe/ZnS, CdSe/CdS/ZnS core/shell QDs), alongside a Lumogen dye-based LSC and a luminophore-free LSC. The study yields several findings: 1) SEBS-g-MA undergoes photochemistry outdoors, 2) SEBS-g-MA accelerates the photodegradation of Lumogen, 3) the power conversion efficiency of CdSe-based QD-LSC drops by 80% due to reduction of the photoluminescence quantum yield, and 4) under illumination SEBS-g-MA protects CuInS₂ and InP-based QDs from degradation, ensuring a stable performance during the entire study. This work thus demonstrates for the first time that the interaction between the luminophores and the matrix is a critical determinant of the long-term success of LSCs. Leveraging on the fact that this is the longest outdoor study to date, we propose design rules for highly efficient and stable QD-LSCs.