A sulfur-rich small molecule as a bifunctional interfacial layer for stable perovskite solar cells with efficiencies exceeding 22

• Published in: Nano energy Vol. 79; p. 105462
• Main Authors: Li, Ming-Hua, Sun, Tian-Ge, Shao, Jiang-Yang, Wang, Yu-Duan, Hu, Jin-Song, Zhong, Yu-Wu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2021
• Subjects: Bifunctional molecules; Defect passivation; Hole-transport Materials; Interface; Perovskite solar cells; Defect passivation; Hole-transport Materials; Bifunctional molecules; Interface; Perovskite solar cells
• ISSN: 2211-2855
• DOI: 10.1016/j.nanoen.2020.105462

Remarkable progress has been made in perovskite solar cells (PSCs) recently. However, the defects present in the perovskite layer act as non-radiative recombination centers to decrease the stability and restrict the further performance improvement of the device. We report herein a sulfur-rich two-dimensional small molecule, SMe-TATPyr, as a bifunctional layer to efficiently passivate the surface defects of perovskite and facilitate the hole transfer at the perovskite/spiro-OMeTAD interface. X-ray photoelectron spectroscopy analyses show that the sulfur atoms of SMe-TATPyr can passivate the uncoordinated Pb2+ defects and suppress the Pb0 defect formation as Lewis bases. As a result, the power conversion efficiency of PSCs is distinctly increased from 20.4% to 22.3%. Moreover, this simple interfacial modification could effectively enhance the stability of unencapsulated PSCs to retain 95% of the initial efficiency after storage for 1500 h at ambient conditions, in contrast to 70% efficiency retention of the device without SMe-TATPyr under the same conditions. [Display omitted] A sulfur-rich two-dimensional small molecule, SMe-TATPyr, has been used as a bifunctional interlayer to efficiently passivate the surface defects of perovskite and facilitate the hole transfer at the perovskite/spiro-OMeTAD interface. The SMe-TATPyr-treated perovskite solar cells demonstrate a remarkable efficiency of 22.3%, along with 95% retention of the initial efficiency under storage for 1500 h at ambient conditions. •A sulfur-rich small molecule is designed as a bifunctional reagent for interfacial defect passivation and hole transfer.•The use of the interfacial layer leads to the efficiency enhancement from 20.4% to 22.3%.•The effect of interfacial defect passivation is fully supported by different physical measurements.