Fabrication And Performance Optimization Of Flexible Dye-sensitized Solar Cell With Film Transfer Method

Flexible dye-sensitized solar cell (FDSSC) is the kind of dye-sensitized solar cell based on flexible conductive substrate. FDSSC is light-weight, bendable and perfectly suitable for charging of portable consumer electronics. This is why FDSSC has been intensively investigated. However, common flexible conductive substrates such as ITO-PET and ITO-PEN can stand only very low temperature of about 150℃,thus FDSSCs are often fabricated under low temperature technique, the device performance is far behind those with high temperature sintering process. In this work, I investigate a novel "film transfer" technique to make FDSSCs on the substrate of ITO-PEN, the general content and results are as follows:1. By screen printing TiO2 paste onto flexible substrate, peeling off and then transferring to ITO-PEN film by static compression, we successful settle the problem that ITO-PEN cannot stand high temperature and fabricated semi-flexible dye-sensitized solar cells with the highest power converting efficiency of 5.3%. we investigated the influence of TBT additive to low temperature bottom layer TiO2 paste and discovered that with a ratio of 5wt% TBT added, the device performed the best,11% improvement than that nothing is added. The study of photoanode film thickness showed that the optimized thickness of TiO2 film is ca. 10μm, pretty thinner than that of traditional DSSCs (14μm-16μm). We also found that a post sintering of photoanode on FTO glass can obviously improve device performance, indicating that there is still more to be done to optimize the bottom TiO2 layer.2. A hydrothermal process was applied to low temperature bottom layer, SEM images shows a great change. Current-Voltage curve test showed that, after 15min hydrothernal treatment, an obvious increase of short-circuit current was achieved, resulting in improvement of Power converting efficiency from 4.75% to 5.3%. electrochemical impedance spectrum analysis indicated better charge transporting property after the treatment.3. A UV/Ozone treatment is applied to photoanode of the device. The treatment eliminated remaining organics and improved light absorption of the solar cells. This settled a solid foundation for further advancement of flexible dye-sensitized solar cells.