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Post‐Treatment Engineering of Vacuum‐Deposited Cs 2 NaBiI 6 Double Perovskite Film for Enhanced Photovoltaic Performance
Author(s) -
Li Peizhou,
Gao Weiyin,
Ran Chenxin,
Dong Hua,
Hou Xun,
Wu Zhaoxin
Publication year - 2019
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201900567
Subject(s) - materials science , photovoltaic system , energy conversion efficiency , perovskite (structure) , annealing (glass) , isopropyl alcohol , solar cell , chemical engineering , optoelectronics , nanotechnology , composite material , electrical engineering , engineering
Lead‐free double perovskite materials have recently shown promising in optoelectronic application. However, the poor solubility of these materials makes them difficult to form a high‐quality thin film via the solution‐processible technology, which leads to the poor photovoltaic performance of a solar cell device. Herein, the vacuum‐evaporated Cs 2 NaBiI 6 double perovskite film with high quality achieved by the post‐treatment engineering is demonstrated. It is found that soaking in isopropyl alcohol (IPA) followed by annealing in dimethyl formamide (DMF) atmosphere can enlarge the size of grains, lower trap‐state density, and remove side product of the Cs 2 NaBiI 6 film. The resulting solar cell devices show a power conversion efficiency (PCE) of 0.21% ( V OC = 0.70 V, J SC = 0.91 mA cm −2 , and fill factor (FF) = 33%), which is tenfold higher than the control device without post‐treatment (PCE = 0.02%, V OC = 0.49 V, J SC = 0.19 mA cm −2 , and FF = 24%). In addition, the device shows robust stability against moisture and oxygen in ambient condition. The vacuum deposition method accompanied with a post‐treatment strategy, in this work, provides an important research direction in improving the quality of a double perovskite film and the PCE of corresponding perovskite solar cells (PSCs).