BaCO3Modification of TiO2Electrodes in Quasi-Solid-State Dye-Sensitized Solar Cells: Performance Improvement and Possible Mechanism

In this paper, a nanoporous TiO 2 electrode modified with an insulating material BaCO 3 is synthesized for quasi-solid-state dye-sensitized solar cells (DSSCs). The formation of BaCO 3 is confirmed from the X-ray photoelectron spectrum (XPS) and Fourier transform infrared (FTIR) spectrum, while the components of the modified TiO 2 film are studied by electron-probe microanalysis (EPMA). We find that BaCO 3 modification remarkably increases dye adsorption, resulting from the fact that the surface of BaCO 3 is more basic than that of TiO 2 . When applied to quasi-solid-state DSSCs, BaCO 3 -modified TiO 2 electrodes have an increased open-circuit photovoltage ( V oc ) and improved overall conversion efficiency (η). The η value improves from 5.53 to 6.96% by 25.9% under 30 mW/cm 2 . The mechanism of BaCO 3 modification is analyzed using the transient photovoltage spectra, open-circuit photovoltage spectra, and dark current measurement. The results indicate that in the presence of BaCO 3, the TiO 2 conduction band shifts to the negative direction.