Charge Transport Layer Engineering toward Efficient and Stable Colloidal Quantum Dot Solar Cells

Lead sulfide (PbS) colloidal quantum dot (CQD) solar cell, as a new type of solution-processed photovoltaic technology, have always attracted great interest. Early studies mainly focused on the surface passivation of CQDs and optimization of device structures. Recently, researchers further developed new charge transport layers and interfacial passivation strategies based on these foundations, which have significantly improved the device efficiency and stability. In this perspective, we summarize the important research progress in transport layer materials, structures, and interfacial passivation of CQD solar cells. We also discuss the remaining challenges and potential development directions for charge transport layers for high-performance and stable PbS CQD solar cells. We hope to draw attention to the enormous potential of charge transport layers in promoting CQD-based optoelectronics toward practical applications.