Photoelectric Thermoelectric Composite Material And Its Application In The Dye Sensitized Solar Cell

Dye-sensitized solar cell(DSSC) because of its low cost, simple preparation method and higher theoretical conversion efficiency merit, has received extensive attention in the past twenty years. It is considered to be the most powerful competitors to silicon solar cells, and its application prospect is generally good. But so far, the actual maximum efficiency of the DSSC also have obvious gap to theory conversion efficiency, so to improve the photoelectric conversion efficiency of the DSSC is still one key problem.Although up to now, nano TiO2 is still the best photoanode material, but the intrinsic conductivity is too low, limiting the transport speed of the electrons in the conduction band, thereby greatly increasing the probability of electron and hole recombination and creating dark current, the short circuit current density of DSSC will be lower. To solve this problem, this paper designs a thermoelectric-photoelectric composite photoanodes, four different quality of thermoelectric materials NaCo2O4 nanofibers doped in TiO2 photoanode to get thermoelectric- photoelectric nano fiber structure composite photoanode and tests the photoelectric properties of DSSC. Owing to the high conductivity of NaCo2O4, the electron transport will be improved. The results show that when nano fiber NaCo2O4 doped quality is 0.3wt%, the conversion efficiency of the DSSC reached 9.1%, the conversion efficiency increased by 8.7%than the pure TiO2 photoanode DSSC.In order to further explore the effects of different morphologies of NaCo2O4 on DSSC. In this paper, we prepare the NaCo2O4 powder by the traditional sol-gel method.Then it is doped into the TiO2 photoelectric prepared thermoelectric-photoelectric powder structure composite photoanode and assembled into DSSC, through a series of test results show that when the doping amount of NaCo2O4 powder is 0.15wt%, the conversion efficiency of the DSSC reaches a maximum of 8.21%, the conversion efficiency increased by 12.6% than the undoped NaCo2O4.This paper continues to prepare TiO2/NaCo2O4 coaxial nanofibers by coaxial electrospinning, then doped into TiO2 photoanode prepared thermoelectric-photoelectric core-shell structure composite photoanode and assembled into DSSC,The results show that when TiO2/NaCo2O4 coaxial nanofibers doped quality is 10wt%,the conversion efficiency of the DSSC reached 9.05%, the conversion efficiency increased by 26.4% than the pure TiO2 photoanode DSSC. This is because of the high conductivity of NaCo2O4 inner core can be as a fast track for transmission electron,The injected electrons in the conduction band of TiO2 was rapidly transferred to the transparent electrode, and reduced the electron hole recombination probability, and increased the short-circuit current density of DSSC; NaCo2O4 also has a very important property, Seebeck effect, namely the temperature difference across the thermoelectric materials will produce temperature difference electromotive force. The results show that when the quality of doped TiO2/NaCo2O4 coaxial nanofibers was 10%, and add ice water on the Pt counter electrode, the conversion efficiency of the DSSC reached10.06%, the conversion efficiency increased by 11.15%.