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Understanding the Photovoltaic Performance of Perovskite–Spirobifluorene Solar Cells
Author(s) -
Song Zhen,
Liu Jiang,
Wang Gang,
Zuo Wentao,
Liao Cheng,
Mei Jun
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201700910
Subject(s) - perovskite (structure) , dopant , photovoltaic system , halide , layer (electronics) , doping , energy conversion efficiency , conductivity , materials science , optoelectronics , transport layer , chemical engineering , nanotechnology , chemistry , inorganic chemistry , organic chemistry , electrical engineering , engineering
Lead halide perovskite solar cells with remarkable power conversion efficiency have attracted much attention in recent years. However, there still exist many problems with their use that are not completely understood, and further studies are needed. Herein, the hole‐transport layer dependence of the photovoltaic performance of perovskite solar cells is investigated in detail. It is found that devices freshly prepared using pristine 2,2′,7,7′‐tetrakis‐( N , N ‐di‐ p ‐methoxyphenylamine)‐9,9′‐spirobifluorene (spiro‐OMeTAD) and Li‐doped spiro‐OMeTAD as hole‐transport layers exhibit S‐shaped current density–voltage curves with poor fill factors. The devices show progressively improved fill factors and efficiencies upon exposure to air, which is attributed to air‐induced conductivity improvement in the spiro‐OMeTAD layer. After introducing a cobalt salt dopant (FK209) into the spiro‐OMeTAD layer, the corresponding devices show remarkable performance without the need of air exposure. These results confirm that the dopant not only increases the conductivity of spiro‐OMeTAD layer, but also tunes the surface potential, which helps to improve charge transport and reduce the recombination loss.