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ZnS shielded ZnO nanowire photoanodes for efficient water splitting

DSpace at IIT Bombay

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Title ZnS shielded ZnO nanowire photoanodes for efficient water splitting
 
Creator KUSHWAHA, A
ASLAM, M
 
Subject Zinc oxide
Nanowire
Core-shell
Photoluminescence
Water splitting
Open circuit photopotential
PHOTOELECTROCHEMICAL HYDROGEN GENERATION
OPEN-CIRCUIT VOLTAGE
SOLAR-CELLS
OPTICAL-PROPERTIES
NANOROD ARRAYS
SENSITIZED ZNO
THIN-FILMS
STABILITY
SHELL
NITROGEN
 
Description A chemical conversion of zinc oxide to zinc sulfide is adapted to create ZnS shell over single crystalline ZnO nanowire. Appearance of an additional peak in x-ray diffraction corresponds to ZnS and strong S 2p(3/2) and S 2p(1/2) peaks in x-ray photoelectron spectroscopy due to Zn-S bonding indicates high quality ZnS shell growth. Reduction in visible light transmittance (approx 15%) is observed in ZnO-ZnS core-shell nanowires which renders higher light absorption. Suppression of defect emission in core-shell nanowires indicates a reduction in surface defects and chemically adsorbed oxygen species. The core-shell geometry also results in an order of increment in charge carrier density (5.3 x 10(18) cm(-3) to 2.8 x 10(19) cm(-3)), i.e. results in an improvement of electrical conductivity and photoelectrochemical performance. Electrochemical solar to hydrogen conversion efficiency is increased to more than double (from 0.15% to 0.38%) due to an improvement in photo-charge carrier separation and collection properties. In comparison to pristine ZnO, photocurrent for ZnO-ZnS core-shell remains same without noticeable fluctuation for few hours, which indicates the ZnS functionalization adds stability to unstable ZnO photoanode. Higher conduction band position of ZnS enhances open circuit photovoltage and reduces photo carrier recombination rate leads to enhancement in photo carrier life time. (C) 2014 Published by Elsevier Ltd.
 
Publisher PERGAMON-ELSEVIER SCIENCE LTD
 
Date 2014-12-28T16:49:52Z
2014-12-28T16:49:52Z
2014
 
Type Article
 
Identifier ELECTROCHIMICA ACTA, 130222-231
0013-4686
1873-3859
http://dx.doi.org/10.1016/j.electacta.2014.03.008
http://dspace.library.iitb.ac.in/jspui/handle/100/16927
 
Language English