Abstract
Harvesting ambient indoor light to power autonomous Internet of Things (IoT) nodes and smart wearable sensors requires photovoltaic architectures optimized for weak photon flux. Quantum dot sensitized solar cells (QDSSCs) offer tunable absorption profiles and low-cost manufacturing, yet conventional chalcogenide-based sensitizers suffer from severe trap-assisted non-radiative recombination under low-light regimes. In this study, we demonstrate high-efficiency QDSSCs sensitized with colloidal all-inorganic cesium lead halide (CsPbBr3−xIx) perovskite nanocrystals (PNCs). By engineering the surface ligand shell via a short-chain 3-mercaptopropionic acid (MPA) solid-state exchange, we significantly improve interfacial electronic coupling between the nanocrystals and the mesoporous titanium dioxide (TiO2) photoanode while effectively passivating deep trap states. Time-resolved photoluminescence spectroscopy confirms accelerated electron extraction kinetics with an average carrier lifetime reduction from 18.4 ns to 2.1 ns upon integration onto TiO2. Under a standard 1000-lux indoor light-emitting diode (LED) illumination (2700 K), the optimized PNC-sensitized device achieves a power conversion efficiency (PCE) of 19.82%, accompanied by an open-circuit voltage (Voc) of 0.812 V and a high shunt resistance of 142.6 kΩ·cm2, which effectively suppresses leakage current. This work demonstrates that surface-engineered perovskite nanocrystals represent a highly promising class of sensitizers for low-light energy harvesting in next-generation smart materials and autonomous nanoelectronics.
