Analytical Review of Spiro‐OMeTAD Hole Transport Materials: Paths Toward Stable and Efficient Perovskite Solar Cells

The hole transport material (HTM) of organic–inorganic perovskite solar cells (PVSCs) plays a very important role for achieving high power conversion efficiency and long-term stability. 2,2’,7,7’-tetrakis[N,N-di(4-methoxyphenyl)amino]-9-9’-spirobifluorene (spiro-OMeTAD) is the first solid-state HTM used in PVSCs has gained tremendous attention during last decade. Herein, concept spirolinkage synthesis spiro-based HTMs discussed, followed by an overview desirable optical electrical properties spiro-OMeTAD. Recent progress improvements analyzed systematically, impacts interface engineering, dopant-free spiro-OMeTAD, novel are reviewed detail. mobility spiro-OMeTAD depends on types dopants doping concentration. Commonly lithium bis(trifluoromethylsulfonyl)imide 4-tert-butylpyridine additives reduce PVSC stability due to hygroscopicity corrosiveness, respectively. effects device techniques improve also discussed. review analysis various methods strategies presented useful research community, providing guidance directions toward further development with improved