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Di‐Spiro‐Based Hole‐Transporting Materials for Highly Efficient Perovskite Solar Cells
Author(s) -
Gao Ke,
Xu Bo,
Hong Chaoshen,
Shi Xueliang,
Liu Hongbin,
Li Xiaosong,
Xie Linghai,
Jen Alex KY
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201800809
Subject(s) - materials science , heteroatom , fluorene , perovskite (structure) , energy conversion efficiency , nanotechnology , optoelectronics , chemical engineering , ring (chemistry) , organic chemistry , polymer , composite material , chemistry , engineering
Hole‐transporting materials (HTMs) are essential for enabling highly efficient perovskite solar cells (PVSCs) to extract and transport the hole carriers. Among numerous HTMs that are studied so far, the single‐spiro‐based compounds are the most frequently used HTMs for achieving highly efficient PVSCs. In fact, all the new spiro‐based HTMs reported so far that render PVSCs over 20% are based on spiro[fluorene‐9,9′‐xanthene] or spiro [cyclopenta [2,1‐b:3,4b′]dithiophene‐4,9′‐fluorene] cores; therefore, there is a need to diversify the design of their structures for further improving their function and performance. In addition, the fundamental understanding of structure–performance relationships for the spiro‐based HTMs is still lagging, for example, how molecular configuration, spiro numbers, and heteroatoms in spiro‐rings impact the efficacy of HTMs. To address these needs, two novel H‐shaped HTMs, G1 and G2 based on the di‐spiro‐rings as the cores are designed and synthesized. The combined good film‐forming properties, better interactions with perovskite, slightly deeper highest occupied molecular orbital, higher mobility and conductivity, as well as more efficient charge transfer for G2 help devices reach a very impressive power conversion efficiency of 20.2% and good stability. This is the first report of demonstrating the feasibility of using di‐spiro‐based HTMs for highly efficient PVSCs.