| In recent years, great progress has been achieved in dye-sensitized solar cells (DSSCs). As a new generation solar cell, DSSCs are low-cost, easy-fabrication and have relatively high light-to-electricity conversion efficiency. A typical DSSC has a sandwich-like structure consisting of a dye-adsorbed photoelectrode and a Pt counter electrode filled with an iodide/triiodide redox electrolyte. In the structure, the photoanode plays a crucial role in determining the light harvest and charge transport properties. By designing the microstructure of photoanode, more light can be adsorbed to generate higher electric current. As a useful microstructure, scattering layers are used in the photoanode to increase the light harvest. Nanoporous TiO2spheres have been deposited on top of the nanocrystalline photoanode as a scattering layer in DSSC to obtain good scattering performance as well as to adsorb more dye. In the present work:1. A hydrothermal method has been used to synthesize anatase TiO2nanoparticles with an average size of15-20nm, which shows better performance than P25when applied in DSSC. By adjusting the pH values of precursors, nanoparticles with different sizes were fabricated.2. Size-controlled monodispersed TiO2spheres were achieved via controlled hydrolysis and condensation of appropriate precursors. Firstly, the synthetic nanoporous TiO2spheres of anatase phase with a diameter ranging from100nm to475nm were used as the scattering layers of DSSCs via a electrophoresis deposition method (EPD). Then, films with controllable thickness were also achieved by changing the time and voltage of EPD. Finally, the effect of the film thickness and sizes of spheres have been taken to study the properties of scattering layers. By using the475nm-sized spheres, a6.3%overall energy conversion efficiency has been achieved, indicating a30%increase compared to photoanode using only nanoparticle film (4.75%), the IPCE reached75%. |
PDF Full Text Request