1 research outputs found
Dye-Anchoring Functional Groups on the Performance of Dye-Sensitized Solar Cells: Comparison between Alkoxysilyl and Carboxyl Groups
We have compared two dye-anchoring
functional groups, alkoxysilyl
and carboxyl groups, to investigate their influence on the performance
of dye-sensitized solar cells. (Dimethylamino)Âazobenzene was selected
as a chromophore possessing a donor–acceptor transition for
the light absorption. Electrochemical and optical measurements were
performed for 4-(dimethylamino)Âazobenzene-4′-carboxylic acid
and 4-(dimethylamino)Âazobenzene-4′-triethoxysilane attached
TiO<sub>2</sub> films. Electrochemical measurements and DFT calculations
indicated almost identical potential energy levels and electron density
of HOMO and LUMO states between these two dyes. Solar cell APCE spectra
and charge recombination kinetics at the dye/TiO<sub>2</sub> interface
revealed almost identical charge-transfer rates/yields from and to
the dye. The difference was observed on improvement of an open circuit
photovoltage (<i>V</i><sub>oc</sub>) by 60 mV and on the
lifetimes of an electron in the TiO<sub>2</sub> conduction band for
the dye with the alkoxysilyl functional group compared to the carboxyl
group, suggesting that an alkoxysilyl functional group is more attractive
to retard the charge recombination reaction between an electron in
the TiO<sub>2</sub> conduction band and an oxidized form of an electrolyte
redox couple. The highest solar energy conversion efficiency of 2.6%
was achieved for dye-sensitized solar cells based on an azobenzene
dye sensitizer under AM1.5<i>G</i>, one sun condition