Abstract
A nanocomposite porous electrode structure consisting of hierarchical iodine-doped zinc oxide (I-ZnO)
aggregates combined with the two simple solution-processed interfacial modifications i.e. a ZnO
compact layer (CL) and a TiO2 protective layer (PL) has been developed in order to understand electron
transport and recombination in the photoanode matrix, together with boosting the conversion efficiency
of I-ZnO based dye-sensitized solar cells (DSCs). Electrochemical impedance spectra demonstrate that
ZnO CL pre-treatment and TiO2 PL post-treatment synergistically reduce charge-transfer resistance and
suppress electron recombination. Furthermore, the electron lifetime in two combined modifications of IZnO
+ CL + PL photoelectrode is the longest in comparison with the other three photoelectrodes. As a
consequence, the overall conversion efficiency of I-ZnO + CL + PL DSC is significantly enhanced to 6.79%,
with a 36% enhancement compared with unmodified I-ZnO DSC. Moreover, the stability of I-ZnO + CL + PL
cell is improved as compared to I-ZnO one. The mechanism of electron transfer and recombination upon
the introduction of ZnO CL and TiO2 PL is also proposed in this work.
Original language | English |
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Pages (from-to) | 258-265 |
Number of pages | 8 |
Journal | Electrochimica Acta |
Volume | 157 |
Early online date | 12 Jan 2015 |
DOIs | |
Publication status | Published - 01 Mar 2015 |