Application of quantum dots in solar cells

Quantum dots (QDs) are potential agents for solar energy conversion due to their size-dependent optoelectronic properties. QD-sensitized solar cells (QDSSCs) are potential candidates to meet the growing demand for clean energy due to facile and low-cost fabrication techniques. High performance is expected in this type of solar cell architecture due to multiple exciton production and energy bandgap tuning in QDs. Various types of QDs have been explored, such as CdS/CdSe, CuInS2, PbS, Zn-Cu-In-Se and perovskite QDs (PQDs). Among all QDs, Cd chalcogenide-based sensitizers, especially CdS and CdSe (CdTe) are the preferred choices for solar cell devices due to easy fabrication, low cost, and performance. This chapter focuses on advances in QDSSCs like cosensitization of CdS/CdSe, introduction of passivation layer (ZnS), annealing temperature, counter electrode modification (Cu2S, CoS, and composites of Cu2S/rGO), polysulfide electrolyte modification, doping of QDs (e.g., Mn), and use of a wide bandgap semiconductor (TiO2/ZnO) to enhance the photon conversion efficiency (PCE). Additionally, PQDs and silicon tandem solar cells exhibit potential characteristics such as low production cost, high PCE (29.5%), and suitable architecture for large-scale production. Here, QDs sensitized solar cells, mechanism, working principle, unique properties, Cd chalcogenide-based, perovskite-based, and other QDs-based solar cells and recent modifications to enhance the PCE are reported.