Vacuum Auxiliary Dye Adsorption And The Wedge In Working Electrode Microstructure On The Properties Of The Dye Sensitized Solar Cell

Dye-sensitized solar cells are thought of a very important clean and renewable energy sources, because of its low cost and simple fabrication process. However, up to now, dye-sensitized solar cells have low conversion efficiency and short lifetime. In this paper, improved dye adsorption process and obconical-patterned microstructure in TiO2films were studied to enhance the performance of dye-sensitized solar cells. The main research work introduced in this paper is as below:1. Enhanced dye loading via vacuum assistant dye adsorption (VADA) process.The effects of the vacuum assistant dye adsorption (VADA) process on dye loading and the performances of the dye sensitized solar cells (DSSCs) were investigated experimentally. The amounts of dyes adsorbed by the TiO2nanoporous films were found to be enhanced about20.7%compared with dyes adsorbed in ambient condition. In accordance, a relative increase of about29%for the short circuit currents (Isc) and32%for the efficiencies (η) were observed for the resulted DSSCs. Photocurrent-voltage measurement indicated that the lifetime of the photogenerated charge carriers changed little. Hence, such improvements were originated from the application of VADA process, which realized full contact between the dye solution and TiO2nanoparticles by driving away the air bubbles concealed in the nanoporous film.2. Enhanced incident sunlight trapping of obconical-patterned microstructure in TiO2films.The effects of obconical-patterned microstruture in TiO2films on incident sunlight trapping and the performances of dye-sensitized solar cells were investigated experimentally. Obconical-patternd TiO2films were fabricated by Silica needle arrays (SNAs) made by the method of tube arrays fabrication and etching (TAFE), obconical-patterned and flat unpatterned TiO2films were fabricated and characterized for comparison. Referring to the research results, by utilization of obconical-patterned TiO2films, open-circuit voltage of DSSC changed little, but the amounts of dyes adsorbed by the obconical-patterned TiO2films were found to be slightly decreased due to the decreased density of TiO2films. In accordance, DSSC based on obconical-patterned TiO2film displayed lower short-circuit current density which was consistent with the decreased dye amounts. However, because of enhanced incident sunlight trapping of obconical-patterned microstruture in TiO2films, DSSC obtained higher fill factor. Finally, DSSC with obconical-patterned TiO2films showed similar conversion efficiency compared to the cell based on a flat unpatterned TiO2film. According to the reseach results, under the precondition of similar conversion efficiency, usage amount of expensive dye decreased by utilization of obconical-patterned TiO2films. This improvement provided a new approach to lower the cost of dye sensitized solar cells.