Solvent Engineering of a Dopant-Free Spiro-OMeTAD Hole-Transport Layer for Centimeter-Scale Perovskite Solar Cells with High Efficiency and Thermal Stability

Min Hu, Xuelian Wu, Wen Liang Tan, Boer Tan, Andrew D. Scully, Lei Ding, Cai Zhou, Yuli Xiong, Fuzhi Huang, Alexandr N. Simonov, Udo Bach, Yi Bing Cheng, Shengxiang Wang, Jianfeng Lu

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24 Citations (Scopus)


High efficiency and environmental stability are mandatory performance requirements for commercialization of perovskite solar cells (PSCs). Herein, efficient centimeter-scale PSCs with improved stability were achieved by incorporating an additive-free 2,2′,7,7′-tetrakis[N,N-di(p-methoxyphenyl)amino]-9,9′-spirobifluorene (spiro-OMeTAD) hole-transporting material (HTM) through simply substituting the usual chlorobenzene solvent with pentachloroethane (PC). A stabilized power conversion efficiency (PCE) of 16.1% under simulated AM 1.5G 1 sun illumination with an aperture of 1.00 cm2 was achieved for PSCs using an additive-free spiro-OMeTAD layer cast from PC. X-ray analysis suggested that chlorine radicals from PC transfer partially to spiro-OMeTAD and are retained in the HTM layer, resulting in conductivity improvement. Moreover, unencapsulated PSCs with a centimeter-scale active area cast from PC retained >70% of their initial PCE after ageing at 80 °C for 500 h, in contrast with less than 20% retention for control devices. Morphological and X-ray analyses of the aged cells revealed that the perovskite and HTM layers remain almost unchanged in the cells with a spiro-OMeTAD layer cast from PC whereas serious degradation occurred in the control cells. This study not only reveals the decomposition mechanism of PSCs in the presence of HTM additives but also opens up a broad range of organic semiconductors for radical doping.

Original languageEnglish
Pages (from-to)8260-8270
Number of pages11
JournalACS Applied Materials & Interfaces
Issue number7
Publication statusPublished - 19 Feb 2020


  • dopant-free
  • hole-transporting materials
  • pentachloroethane
  • perovskite solar cell
  • radical
  • spiro-OMeTAD
  • stability

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