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Interface Engineering via Sputtered Oxygenated CdS:O Window Layer for Highly Efficient Sb 2 Se 3 Thin‐Film Solar Cells with Efficiency Above 7%
Author(s) -
Guo Liping,
Zhang Baiyu,
Ranjit Smriti,
Wall Jacob,
Saurav Swapnil,
Hauser Adam J.,
Xing Guozhong,
Li Lin,
Qian Xiaofeng,
Yan Feng
Publication year - 2019
Publication title -
solar rrl
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.544
H-Index - 37
ISSN - 2367-198X
DOI - 10.1002/solr.201900225
Subject(s) - chalcogenide , materials science , cadmium telluride photovoltaics , band gap , antimony , energy conversion efficiency , optoelectronics , analytical chemistry (journal) , chemical engineering , chemistry , metallurgy , engineering , chromatography
Antimony chalcogenide Sb 2 Se 3 is an emerging photovoltaic absorber due to its appropriate bandgap (≈1.1 eV), high absorption coefficient (>10 5 cm −1 ), suitable p‐type conductivity, low toxicity, earth abundance, and excellent stability. However, the stringent growth condition and low photovoltage limit its power conversion efficiency (PCE). Herein, via a combined theoretical and experimental study, interface engineering via an oxygenated cadmium sulfide (CdS) window layer (CdS:O) is found to be an effective approach to improve the device performance of CdS:O/Sb 2 Se 3 solar cells. The sputtered oxygenated CdS:O window layer can be used to replace conventional chemical‐bath‐deposited CdS window layer in the Sb 2 Se 3 devices. The best PCE of 7.01% is demonstrated in the superstrate configuration of fluorine‐doped SnO 2 /CdS:O/Sb 2 Se 3 /graphite with a high open‐circuit voltage of 0.432 V, where Sb 2 Se 3 is fabricated using the close space sublimation technique. The interfacial diffusion between Sb 2 Se 3 and sputtered CdS:O is significantly suppressed by introducing oxygen at the interface, which prevents Cd diffusion and the formation of Cd interstitials. Combined device physics characterizations and theoretical calculations reveal that oxygen in the CdS:O/Sb 2 Se 3 interface can increase depletion region, built‐in voltage, and reduce interfacial recombination. These findings provide the guidance to optimize quasi‐one‐dimensional non‐cubic earth‐abundant chalcogenide photovoltaic devices through interface engineering.