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Download fileIn-Situ and Green Method To Prepare Pt-Free Cu2ZnSnS4 (CZTS) Counter Electrodes for Efficient and Low Cost Dye-Sensitized Solar Cells
journal contribution
posted on 2015-11-02, 00:00 authored by Shanlong Chen, Aichun Xu, Jie Tao, Haijun Tao, Yizhou Shen, Lumin Zhu, Jiajia Jiang, Tao Wang, Lei PanA novel in-situ and green method
with the combination of TiCl4 pretreatment and solvothermal
growth was proposed to prepare
the Pt-free Cu2ZnSnS4 (CZTS) counter electrodes
(CEs) on FTO substrate. It was found that TiCl4 pretreatment
toward the substrates was crucial to a high quality and high efficiency
CZTS film, which consists of nanosheet and nanoparticle structure.
The highly crystallized nanosheets were assembled from kesterite structure
CZTS nanocrystals, with an average diameter of 10–30 nm. The
detailed morphology, crystal structure, and composition of the CZTS
nanostructures were characterized by SEM, TEM, SAED, XRD, Raman, and
EDS analysis, respectively. Electrocatalytic abilities of the films
toward I–/I3– were
verified through cyclic voltammograms (CV), electrochemical impedance
spectroscopy (EIS), and Tafel polarization measurements. A maximum
power conversion efficiency of 5.65% was achieved for a cell with
CZTS 3, under 100 mW/cm2, which was higher than that of
a cell with a commercial Pt counter electrode (4.96%). This high efficiency
was mainly attributed to the good bonding strength between CZTS films
and FTO substrate (RS = 4.41 Ω cm2), and higher electron-transfer process at the electrolyte/CE
interface (high JSC), along with superior
electrochemical catalytic ability (RCt = 2.40 Ω cm2). The in-situ prepared CZTS CEs are
proven to be suitable for high efficiency Pt-free dye-sensitized solar
cells (DSSCs), leading to significantly decrease of the cell cost
and simplification of preparation process.