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Enhanced Visible Photovoltaic Response of TiO2 Thin Film with an All-Inorganic Donor–Acceptor Type Polyoxometalate
journal contribution
posted on 2015-06-24, 00:00 authored by Jian-Sheng Li, Xiao-Jing Sang, Wei-Lin Chen, Lan-Cui Zhang, Zai-Ming Zhu, Teng-Ying Ma, Zhong-Min Su, En-Bo WangIn the field of material chemistry,
it is of great significance to develop abundant and sustainable materials
for solar energy harvesting and management. Herein, after evaluating
the energy band characteristics of 13 kinds of polyoxometalates (POMs),
the trisubstituted POM compound K6H4[α-SiW9O37Co3(H2O)3]·17H2O (SiW9Co3) was first studied due to
its relatively smaller band gap (2.23 eV) and higher lowest unoccupied
molecular orbital (LUMO) level (−0.63 V vs NHE). Additionally,
the preliminary computational modeling indicated that SiW9Co3 exhibited the donor–acceptor (D–A) structure,
in which the cobalt oxygen clusters and tungsten skeletons act as
the electron donor and electron acceptor, respectively. By employing
SiW9Co3 to modify the TiO2 film,
the visible photovoltaic and photocurrent response were both enhanced,
and the light-induced photocurrent at 420 nm was improved by 7.1 times.
Moreover, the highly dispersive and small sized SiW9Co3 nanoclusters loading on TiO2 were successfully
achieved by fabricating the nanocomposite film of {TiO2/SiW9Co3}3 with the layer-by-layer
method, which can result in the photovoltaic performance enhancement
of dye-sensitized solar cells (DSSCs), of which the overall power
conversion efficiency was improved by 25.6% from 6.79% to 8.53% through
the synergistic effect of POMs and Ru-complex.