Ligand-engineered Cu–Zn–In–Se quantum dots for flexible laminated luminescent solar concentrators

Abstract

Luminescent solar concentrators (LSCs) are promising for building-integrated photovoltaics, where color tunability, form factor, and scalability are often more important than absolute efficiency. Here, a major challenge consists in developing eco-friendly luminophores with stable and controllable optical properties. Cu-doped Zn–In–Se (CZISe) quantum dots (QDs) are surface-passivated with trioctylphosphine (TOP), providing a model system to examine the role of ligand engineering in heavy-metal-free emitters. TOP modification increases the photoluminescence quantum yield (PLQY) from 22 ± 5% to 67 ± 5%, extends carrier lifetime, and induces a blue-shifted emission, reflecting improved surface passivation and altered excitonic dynamics. These changes nearly double the optical efficiency of laminated LSCs compared to devices with unmodified QDs. Importantly, this study reports flexible laminated LSCs fabricated with polyvinyl chloride (PVC) substrates, which maintain stable optical performance under mechanical deformation. This demonstration establishes ligand modification and flexible device architectures as complementary approaches for advancing the practical applicability of eco-friendly LSCs.