Peiqing Wang

Novel core–shell TiO2 microsphere scattering layer for dye-sensitized solar cells

Core–shell TiO2 microspheres were synthesised by a one step solvothermal method in ethanol solvent. The single anatase TiO2 core–shell structure exhibited high reflectance and large surface area due to its special structure. When applied in the dye-sensitized solar cells (DSCs), this micro-spherical core–shell structure effectively enhanced light harvesting and led to the increase of the photocurrent of the DSCs. As a result, 29% improvement in conversion efficiency of DSCs was achieved after introducing the core–shell TiO2 scattering layer. A comparative experiment between the core–shell structure and a solid structure further confirmed that the core–shell structure is more beneficial for light scattering and photovoltaic performance. The excellent properties of the microspherical core–shell TiO2 make it a promising candidate as a scattering material for DSCs.

Sulfur-doped TiO2 nanocrystalline photoanodes for dye-sensitized solar cells

Sulfur-doped TiO2 photoanode was prepared by hydrothermal method, and then characterized and analyzed through XRD, UV-vis, and XPS. The results showed that: Sulfur-doped TiO2 doped by sulfur was anatase; Sulfur-doped TiO2 atoms improved visible light absorption ability of TiO2; The performance of DSSCs doped by sulfur improved markedly, in which 0.770 g thiourea sample performed the best. Its open-circuit voltage was 0.72 V, short-circuit current density was 16 mA·cm −2 , and photoelectric conversion efficiency reached 14.82% high. The improvement of efficiency is resulted from the Sulfur-doped which leads to the following effects: more electrons from dye are injected into the TiO2 nanometer crystal, the electron transfer rate is enhanced, therefore short circuit current density of the battery is increased, finally the efficiency of the battery is improved.

The characterization of nitrogen doped TiO2 photoanodes and its application in the dye sensitized solar cells

In this paper, nitrogen doped TiO2 photoanodes were achieved by calcining the mixture of urea and the commercial P25 nanoparticles slurry. Its application in the dye sensitized solar cells was examined. X-ray photoelectron spectroscopy indicated the N substituted the O atoms and formed N-Ti-O bonds. The optical band gap of the doped TiO2 photoanodes was reduced. From the photoelectrochemical experiments, it is known that nitrogen doping introduced new energy states above the valence band of the TiO2 photoanode, which lead to the visible light response and increased electron density. Optimized photo to electric conversion efficiency of the DSSC 6.71% is obtained with short current density (Jsc) of 14.3 mA cm−2, open circuit voltage (Voc) of 0.669 V and fill factor (FF) of 0.706 by the nitrogen doping, compared with 5.31% of the undoped one (Jsc of 13.2 mA cm−2, Voc of 0.638 V and FF of 0.624) at 0.99sun AM1.5, which is mainly due to the energy band structure change and partly the morphology change of the p...

Carbon nanotube based flexible counter electrode for quasi-solid state dye sensitized solar cells

Low temperature fabrication of carbon nanotube based conductive composite polymer (CNT-CCP) film on conductive flexible substrate indium tin oxide coated polyethylene terephthalate film (ITO-PET) is developed as a low cost alternative to the Pt counter electrode especially for flexible quasi-solid state dye sensitized solar cells (DSSCs). The formation of three-dimensional carbon nanotube network provides the conductivity pathway which is improved with the carbon nanotube content and the film thickness increase. More importantly, the conductivity of CNT-CCP films greatly influences the performance of DSSCs. With high conductivity, good catalytic activity and especially the good consistence of the CNT-CCP with the polymer electrolyte, flexible CNT-CCP/ITO-PET counter electrode for the DSSC with the quasi-solid state composite polymer electrolyte exhibits performance of 4.24% (0.95Sun, AM1.5), which is 87% of the quasi-solid state DSSC with Pt counter electrode (4.87%). It indicates the CNT-CCP type counter...