Stoichiometry‐Controlled Cobalt Sulfide‐Based Hole Transport Layers for Perovskite Solar Cells (Small 48/2025)

Perovskite Solar Cells Cobalt sulfides are commonly found as nonstoichiometric minerals. Precise adjustment of the Co:S ratio in CoS, Co4S3, and Co9S8 yields stoichiometrically defined crystals that serve as inorganic hole transport layers in perovskite solar cells. Stoichiometry tuning tailors band alignment and hole extraction, introducing a stoichiometry-guided strategy for hole transport material design. More in article number 2505726, Min Jae Ko and co-workers.