Thiol Groups Reutilization on Chemical Bath Deposited Tin Oxide Surface Achieving Interface Anchoring and Defects Passivation for Enhancing the Performance and Stability of Perovskite Solar Cells.

Due to its simple process and adaptability to large-area deposition, chemical bath deposition (CBD) is one of the preparation methods for the SnO ₂ layer in highly efficient "n-i-p" structured perovskite solar cells (PSCs). However, the residual thioglycolic acid (TGA) on the CBD-SnO ₂ surface affects the stability of PSCs and the carrier transport at the CBD-SnO ₂ /perovskite interface, hindering the further development of this method. This work demonstrates a method for the reutilization of surface groups to construct molecular bridges. This strategy utilizes the substitution reaction between the residual thiol group on the CBD-SnO ₂ surface and the iodine group of iodoacetamide (IAM) to form the IAM structure. The IAM structure not only assists the perovskite grain crystallization but also increases the electronic cloud density of the CBD-SnO ₂ surface. Consequently, the charge mobility of the CBD-SnO ₂ is enhanced and the energy band alignment at the CBD-SnO ₂ /perovskite interface is optimized. A champion device with the IAM structure achieved a power conversion efficiency (PCE) of 22.41% while it maintained 80% of its original PCE after placing at 65 °C in nitrogen filled atmosphere for over 300 h and in an environment at 25 °C and 50 ± 5% relative humidity for over 1000 h, respectively.
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