Efficient and stable perovskite solar cells via oxalic acid doped SnO2 nanocrystals with surface-defect passivation

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 702; p. 135052
• Main Authors: Jiang, Lulu, Li, Qi, Li, Bo, Guo, Shuaike, Li, Shaojie, Zhang, Xiaonan, Tang, Xiaodan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.12.2024
• Subjects: Carrier mobility; Electron-transporting layer; Energy band regulation; Surface modification of SnO2 nanocrystals; Electron-transporting layer; Energy band regulation; Carrier mobility; Surface modification of SnO2 nanocrystals
• ISSN: 0927-7757
• DOI: 10.1016/j.colsurfa.2024.135052

The electron extraction and transfer play a crucial role in high performance of perovskite solar cells (PSCs). Tin dioxide (SnO2), with the high electrical conductivity and low photocatalytic activity, has been reported to be one of the most advantageous electron-transporting layers (ETL) in PSCs. However, a large number of non-radiative recombination defects have been reported in SnO2, which are attributed to the low tunability and lower dispersibility. Here, we propose a ligand-assisted tuning strategy based on the oxalic acid (OA) modification to control the SnO2 film and interfacial structure. This strategy can effectively inhibit the particle aggregation of SnO2 film. In addition, the bonding interaction between CO in the ligand and Sn in SnO2 and Pb atoms in the perovskite reduces the interfacial contact impedance and enhances the electron extraction. As a result, an impressive PCE of 22.68 %, a fill factor exceeding 0.82 and a Voc of 1.15 V were successfully obtained. In addition, the unencapsulated PSCs can maintain an initial efficiency of 93 % upon exposure to ambient air for 500 h. [Display omitted]