Quantum Dot Sensitized Solar Cells (QDSSCs): Materials, Performance, and Prospects

Quantum Dot Sensitized Solar Cells (QDSSCs) represent an advanced class of third-generation photovoltaic devices that utilize the quantum confinement effects of semiconductor nanocrystals for enhanced light harvesting. This study explores CdSe, InP, and CuInS₂-based QDSSCs synthesized via SILAR and hot-injection techniques, emphasizing tunable bandgaps, multiple exciton generation (MEG), and surface passivation for improved performance. UV–V is spectra revealed bandgaps between 1.5–2.5 eV, dependent on particle size. Under AM 1.5G illumination, CdSe-based devices achieved 5.0% power conversion efficiency (PCE), outperforming InP (3.3%) and CuInS₂ (2.7%) devices. Electrochemical impedance spectroscopy confirmed that CdSe exhibited the lowest charge-transfer resistance and highest electron lifetime. A case study using Delhi’s July 2025 solar irradiance data demonstrated 21.6% efficiency for a 3 kW system and an average output of 17.21 kWh/day for a 10 kW installation. These findings indicate that while CdSe QDs deliver higher efficiency, eco-friendly alternatives such as InP and CuInS₂ offer sustainable solutions. Integrating solid-state electrolytes, core–shell architectures, and scalable deposition methods can drive QDSSCs toward commercialization in flexible, wearable, and building-integrated photovoltaic.