TY - JOUR
T1 - Double Perovskite Cs2BBiX6 (B = Ag, Cu; X = Br, Cl)/TiO2 Heterojunction
T2 - An Efficient Pb-Free Perovskite Interface for Charge Extraction
AU - Feng, Hong Jian
AU - Deng, Wan
AU - Yang, Kang
AU - Huang, Jinsong
AU - Zeng, Xiao Cheng
N1 - Funding Information:
We acknowledge helpful discussions with Dr. Jun Dai and Dr. Minggang Ju. H.-J. F. was financially supported by the National Natural Science Foundation of China (NSFC) under Grant No. 51672214, No. 11304248 and No. 11247230, the Natural Science Basic Research Plan in Shaanxi Province of China (Program No. 2014JM1014), the Scientific Research Program Funded by Shaanxi Provincial Education Department (Program No. 2013JK0624), the Fund Program for the Scientific Activities of Selected Returned Overseas Professionals in Shaanxi Province of China and Youth Bai-Ren (100 Talents Plan) Project in Shaanxi Province of China. X.C.Z. and J.H. were supported by the National Science Foundation (NSF) through the Nebraska Materials Research Science and Engineering Center (MRSEC) (Grant No. DMR-1420645) and an NSF EPSCoR Track 2 grant (OIA-1538893).
PY - 2017/3/2
Y1 - 2017/3/2
N2 - Motivated from the recent success in synthesizing bismuth-based double perovskites (J. Am. Chem. Soc. 2016, 138, 2138-2141), we perform a comprehensive study of interfacial properties of bismuth-based double perovskites Cs2AgBiX6 (X = Br, Cl) and TiO2 interfaces. The bismuth-based double perovskites possess desirable electronic and optical properties as excellent light absorber and thus may serve as lead-free alternatives to the organic-inorganic perovskites. On the basis of density functional theory computation, we systematically study the Cs2BBiX6 (B = Ag, Cu; X = Br, Cl)/TiO2 interfaces and analyze the trend of charge transfer across the interfaces. We find that the Cs4X4 (X = Br and Cl)/TiO2-mediated interfaces are prospective interfaces for charge extraction and separation due largely to the withdrawn trap states for the TiO2 part when in contact with the Cs4X4 termination. Moreover, the ionic interaction and charge redistribution across the specific interfaces can lead to the appropriate band alignment, reduced band gap for the rock-salt double perovskite part, and smooth gradient distribution for the locally projected density of states along the normal direction to the interfaces, further facilitating the charge transfer. Overall, we predict that bismuth-based double perovskites Cs2AgBiX6 (X = Br, Cl) and TiO2 interfaces are highly efficient for charge extraction, suggesting high potential for interfacial engineering optoelectronic devices.
AB - Motivated from the recent success in synthesizing bismuth-based double perovskites (J. Am. Chem. Soc. 2016, 138, 2138-2141), we perform a comprehensive study of interfacial properties of bismuth-based double perovskites Cs2AgBiX6 (X = Br, Cl) and TiO2 interfaces. The bismuth-based double perovskites possess desirable electronic and optical properties as excellent light absorber and thus may serve as lead-free alternatives to the organic-inorganic perovskites. On the basis of density functional theory computation, we systematically study the Cs2BBiX6 (B = Ag, Cu; X = Br, Cl)/TiO2 interfaces and analyze the trend of charge transfer across the interfaces. We find that the Cs4X4 (X = Br and Cl)/TiO2-mediated interfaces are prospective interfaces for charge extraction and separation due largely to the withdrawn trap states for the TiO2 part when in contact with the Cs4X4 termination. Moreover, the ionic interaction and charge redistribution across the specific interfaces can lead to the appropriate band alignment, reduced band gap for the rock-salt double perovskite part, and smooth gradient distribution for the locally projected density of states along the normal direction to the interfaces, further facilitating the charge transfer. Overall, we predict that bismuth-based double perovskites Cs2AgBiX6 (X = Br, Cl) and TiO2 interfaces are highly efficient for charge extraction, suggesting high potential for interfacial engineering optoelectronic devices.
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U2 - 10.1021/acs.jpcc.7b00138
DO - 10.1021/acs.jpcc.7b00138
M3 - Article
AN - SCOPUS:85022008832
VL - 121
SP - 4471
EP - 4480
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 8
ER -