Research On The Properties Of The Dye Sensitized Solar Cell Based On The Binary Ionic Liquid Electrolyte

Dye-sensitized solar cell(DSSC), as a representitave of the third-generation new thin film solar cell, has become a hotspot in the optoelectronics field. As an important part in the dye-sensitized solar cell, the electrolyte plays a role of transporting charges. Although the conventional electrolyte, contianing the liquid organic solvent,has advantages of low viscosity, high diffusion coefficient and so forth, this will result in the limitation of the durability and long-term stability of DSSCs due to the poor light and heat stability of the liquid organic solvent.Room temperature ionic liquids has features of good thermal stability, chemical stability and so on when compared with the conventional organic solvents. Therefore, the durability and long-term stability of DSSCs can be effectively enhanced with applying room temperature ionic liquids as an novel organic solvent in the electrolyte. However, the photoelectric conversion efficiency of the dye-sensitized solar cell based on the room temperature ionic liquid is generally lower, which is brought by the high viscosity of ionic liquid.So it is of great significance to improve the opto-electronic property of the dye-sensitized solar cell based on room temperature ionic liquids.The main work involved in this thesis contained the following three parts :Fisrtly, the production process for the standard device under the available experimental conditions was mastered and performance parameters of the developed standard device could reach the normal level basically, which was based on the in-depth understanding the working mechanisim of the device. Then the laboratory preparation process of the dye-sensitized solar cell based on the room temperature ionic liquid electrolyte was focused on researching with combining experimental conditions.Then, the different volume ratio of the binary ionic liquid, the concentration of additives and iodine in the electrolyte were studied systematically with the control variable method by setting the experimental control group. The opto-electronic performance of the dye-sensitized solar cell was enhance through the above modifying optimization research on the performance of the binary room temperature ionic liquid electrolyte systematically. It was found that an average photoelectric conversion efficiency of 6.35% was achieved with applying the optimized electrolyte, while the maximum one could reach up to 6.63%. It also showed higher PCE than the banchmark value of 5.37% achieved with the same binary RTIL system reported in public, constituting an average improvement of 18.2%.Working principles were analyzed with representative electrolytes and corresponding devices by electrochemical impedance spectroscopy, Tafel polarization curves, cyclic voltammetry scans and incident-photo-conversion efficiency data. It was found that the enhancement was mainly contributed from the reduction of overall internal resistance of the device, leading to the improvement of short circuit current. Durability tests were measured after storing RTIL-DSSCs under dark conditions at room temperature. The long-term performance of device could be maintained after modifying. This work demonstrates the binary RTIL-DSSC can be improved effectively and stably by incorporating proper concentration of additive salts and iodine into the electrolyte, providing a practical way to solve the low efficiency problem existing in RTIL-DSSC universally.