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Extending the Photovoltaic Response of Perovskite Solar Cells into the Near‐Infrared with a Narrow‐Bandgap Organic Semiconductor
Author(s) -
Zhao Xiaoming,
Yao Chao,
Liu Tianran,
Hamill J. Clay,
Ngongang Ndjawa Guy Olivier,
Cheng Guangming,
Yao Nan,
Meng Hong,
Loo YuehLin
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201904494
Subject(s) - materials science , perovskite (structure) , photocurrent , optoelectronics , semiconductor , energy conversion efficiency , chromophore , band gap , photovoltaic system , organic semiconductor , active layer , absorption (acoustics) , layer (electronics) , nanotechnology , photochemistry , chemistry , organic chemistry , ecology , composite material , biology , thin film transistor
Typical lead‐based perovskites solar cells show an onset of photogeneration around 800 nm, leaving plenty of spectral loss in the near‐infrared (NIR). Extending light absorption beyond 800 nm into the NIR should increase photocurrent generation and further improve photovoltaic efficiency of perovskite solar cells (PSCs). Here, a simple and facile approach is reported to incorporate a NIR‐chromophore that is also a Lewis‐base into perovskite absorbers to broaden their photoresponse and increase their photovoltaic efficiency. Compared with pristine PSCs without such an organic chromophore, these solar cells generate photocurrent in the NIR beyond the band edge of the perovskite active layer alone. Given the Lewis‐basic nature of the organic semiconductor, its addition to the photoactive layer also effectively passivates perovskite defects. These films thus exhibit significantly reduced trap densities, enhanced hole and electron mobilities, and suppressed illumination‐induced ion migration. As a consequence, perovskite solar cells with organic chromophore exhibit an enhanced efficiency of 21.6%, and substantively improved operational stability under continuous one‐sun illumination. The results demonstrate the potential generalizability of directly incorporating a multifunctional organic semiconductor that both extends light absorption and passivates surface traps in perovskite active layers to yield highly efficient and stable NIR‐harvesting PSCs.