title: Improved charge transfer and photoelectrochemical performance of CuI/Sb2S3/TiO2 heterostructure nanotube arrays.
abstract: Charge transfer is important for the performance of a photoelectrochemical cell. Understanding photogenerated charge accumulation and separation is mandatory for the design and optimisation of photoelectrochemical cells. Unique stacked and embedded heterostructure of Sb2S3/TiO2 nanotube arrays (NTAs) was fabricated through anodic oxidation with the hydrothermal method. Surface photovoltage spectroscopy, phase spectra and photoluminescence measurements were performed to explore the mechanism by which the inorganic hole transport material CuI affects the charge transfer and photoelectrochemical properties of Sb2S3/TiO2 heterostructure NTAs. The interfacial separation and transport of photoinduced charge carriers were also examined by applying current-voltage characteristics (J-V), incident-photon-to-current conversion efficiency (IPCE) and Mott-Schottky techniques. Results show that CuI acts not only as a hole-conducting and electron-blocking material but also as a light-absorbing material in the ultraviolet range. Efficient charge transfer processes exist in CuI/Sb2S3/TiO2 heterostructure NTAs. The photoelectrochemical performance of CuI/Sb2S3/TiO2 heterostructure NTAs is dramatically improved. Under AM 1.5G illumination at 100mW/cm(2), the short-circuit current density and open-circuit voltage are 3.51mA/cm(2) and 0.87V, respectively. The photoelectric conversion efficiency of CuI/Sb2S3/TiO2 heterostructure NTAs (0.95%) is 36% higher than that of Sb2S3/TiO2 heterostructure NTAs (0.66%).
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity and New Energy R&D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031, China. Electronic address: yf@home.swjtu.edu.cn.
authors.forename: Feng
authors.initials: F
authors.lastname: Yang
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity and New Energy R&D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031, China.
authors.forename: Jinfang
authors.initials: J
authors.lastname: Xi
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity and New Energy R&D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031, China.
authors.forename: Li-Yong
authors.initials: LY
authors.lastname: Gan
authors.affiliation: School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30318, USA.
authors.forename: Yushu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity and New Energy R&D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031, China.
authors.forename: Shuangwei
authors.initials: S
authors.lastname: Lu
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity and New Energy R&D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031, China.
authors.forename: Wenli
authors.initials: W
authors.lastname: Ma
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity and New Energy R&D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031, China; National Engineering Laboratory for Superconducting Materials, Western Superconducting Technologies Co. Ltd, Xi'an, China.
authors.forename: Fanggong
authors.initials: F
authors.lastname: Cai
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity and New Energy R&D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW, Australia.
authors.forename: Cuihua
authors.initials: C
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Advanced Technology of Materials (Ministry of Education of China), Superconductivity and New Energy R&D Center, Mail Stop 165#, Southwest Jiaotong University, Chengdu, Sichuan 610031, China; School of Materials Science and Engineering, University of New South Wales, Sydney, 2052 NSW, Australia. Electronic address: yzhao@home.swjtu.edu.cn.
authors.forename: Yong
authors.initials: Y
authors.lastname: Zhao
keywords: Charge transfer; CuI; Hole conductor; Photoelectrochemical performance; Sb(2)S(3)/TiO(2) heterostructure NTAs