Recent research progress in surface ligand exchange of PbS quantum dots for solar cell application

Colloidal quantum dots (CQDs) are considered as next-generation semiconductors owing to their tunable optical and electrical properties depending on their particle size and shape. The characteristics of CQDs are mainly governed by their surface chemistry, and the ligand exchange process plays a crucial role in determining their surface states. Worldwide studies toward the realization of high-quality quantum dots have led to advances in ligand exchange methods, and these procedures are usually carried out in either solid-state or solution-phase. In this article, we review recent advances in solid-state and solution-phase ligand exchange processes that enhance the performance and stability of lead sulfide (PbS) CQD solar cells, including infrared (IR) CQD photovoltaics.