Research On Carbon Counter Electrode For Dye Sensitized Solar Cell

In this thesis, we have systematically studied the green synthesis of platinum nanoparticle and its application in low-Pt loading carbon counter electrode (CE); the stability of Ti-hydrogel modified carbon counter electrode; the novel counter electrode based on grapheme aerogel and its application in dye sensitized solar cell (DSSC). The main results and achievements are as following:1. Optimizing the parameters of the DSSC assembly process based on carbon counter electrode, In our research system, adding carbon black and graphite at the weight ratio of1:3in the carbon paste, the DSSC based on the as prepared carbon CE has the best performance. On the other side, adding the hydroxyethyl cellulose at the weight ratio of2.5%, the device showed the best power conversion efficiency (5.6%).2. We report a rapid and effective green chemistry route of the synthesis of Pt nanoparticles (PtNPs). Under optimized conditions, the PtNPs were found to distribute uniformly in a narrow size range of3.6to4.1nm and exhibit high stability in the colloids. In addition, these nanoparticles, having advantages of high surface area, narrow distribution and mono-dispersivity, were applied to enhance the catalytic activities of low-cost carbon based CEs for DSSCs. Consequently, the efficiencies of the cells showed a promising improvement from5.7%(of a typical carbon CE) to6.4%by using the carbon/PtNPs composite CE.3. A6.4%high efficiency Pt/carbon electrode was used in DSSCs with combination of low-cost, low Pt-loading and easy-fabrication. The effect of Pt content in carbon counter electrodes and the corresponding performance of DSSCs were investigated. Electrochemical measurement indicated that the optimized Pt content was1.00wt%and the catalytic activity of Pt/carbon counter electrode was saturated in device at this content. Low Pt-loading and high efficiency highlight the potential application of this Pt/carbon counter electrode in low-cost DSSC.4. We described a systematic investigation of the stability of a carbon/TiO2 counter electrode for use in DSSCs. In this system, nanoparticle additives were introduced by adding Ti-hydrogel. The additives then bound carbon particles and enhanced the adhesion of carbon materials to the conductive substrate. After introducing the Ti-hydrogel into the carbon paste, the carbon/Ti-hydrogel composited counter electrode (HC-CE) showed a better conductivity and stability compared with that of the carbon counter electrode (C-CE), while the catalytic activity was not influenced. The device based on the HC-CE showed superior power conversion efficiency (6.3%) and long-term stability over the device based on the C-CE (5.8%).5. A novel carbon CE were fabricated with graphene areogel. Though the Raman, SEM and EDS test, the product have been proved to be the graphene areogel. The as prepared graphene has large surface area though the BET test. However, the catalytic activity of this graphene areogel towards I-/I3-redox was limited. The DSSC based on this graphene areogel CE showed power conversion efficiency of1.43%.