Multidentate Coordination Induced Crystal Growth Regulation and Trap Passivation Enables over 24 Efficiency in Perovskite Solar Cells

摘要

Crystal growth regulation has become an effective solution to reduce thedefects at grain boundaries (GBs) and surfaces of perovskite films for betterphotovoltaic performances. Oxime acid materials are maturely used as selectivecollectors in the flotation separation of oxide minerals. Such materials,showing a strong coordination effect and high selectivity with lead, mayhave great potential in controlling the crystal growth and passivating thedefect of perovskite film, which are rarely applied in perovskite solar cells(PerSCs). Herein, an oxime acid-based material with multi-coordination sites,ethyl 2-(2-aminothiazole-4-yl)-2-hydroxyiminoacetate (EHA), is incorporatedinto the PbI_2 precursor solution to fabricate high-performance PerSCs usinga two-step method. The multidentate coordination effect of EHA can linkand integrate the PbI_2 colloidal clusters to achieve pre-aggregation in thePbI_2 precursor solution, facilitating the sequent crystal growth progress ofperovskite film. Meanwhile, EHA can connect grains and fill GBs, which isfavorable for charge transfer and passivating both Pb-Ⅰ anti-site and iodinevacancy defects. As a result, the optimal devices show an enhanced efficiencyof 24.1 and excellent humidity and thermal stability. This work affords apromising strategy to fabricate efficient and stable PerSCs via multidentatecoordination-induced crystallization control and GB passivation.