Multi-Hydroxyl and Chloric Buried Interface Bridges Enable Synergistically High-Efficiency Perovskite Solar Cells

Abstract

Defects at the interface between perovskite and carrier transport layer are ≈100 times more prevalent than those within perovskite bulk, potentially serving as non-radiative recombination centers to adversely affect carrier extraction and transport. Here, a green pyridoxine hydrochloride (PDHC) is introduced into SnO₂ quantum dots (QDs) solution. The resulting surface chloritization of SnO₂ QDs not only passivates the interface defects, thereby strengthening the interface contact among SnO₂ QDs, but also chemically interconnects SnO₂ QDs with perovskite, thereby forming a very stable interlayer. These promote to establish the carrier transport bridges at the buried interfaces for efficient electron-transportation and -extraction. Under its organic group coordination, high-quality perovskite films are formed via heterogeneous nucleation on the perovskite precursor film, effectively suppressing bulk defects, which mitigates the nonradiative recombination and extends the carrier lifetime. Consequently, the PDHC-based perovskite solar cells achieve an improved efficiency from 24.18 to 25.07%. After 2520 h storage, the unencapsulated devices retained ≈90% of their initial efficiency, exceeding those of control devices which retained only 65% of their initial efficiency, along with 9.4 and 3.8-fold improvement for thermal and light stability.