The Research Of Preparation And Photoelectric Properties Of D-D-Ï€-A Type Triphenylamine-based Dyes

In the21st century, with the growing consumption of coal, oil, natural gas andother non-renewable energy on earth, the energy is sufficient or not, which has becomethe bottleneck of restricting a rapid socio-economic development. Since the outbreak ofthe oil crisis in the70s of the last century, more and more countries are aware of theimportance of energy development, so they began to turn their attention to the newclean renewable energy field. Based on the continuous development of nanotechnology,Swiss Federal Professor Michael Gr tzel and his research team developed the solarcells-dye-sensitized (DSSCs) in1991, whose photoelectric conversion efficiency hasreached to12.3%up to now. The technology bottleneck of DSSCs is photoelectricconversion efficiency and stability, but the low cost of manufacture and simple structureof DSSCs have got more and more attention, which is known as a typical representativeof the third generation of solar cells. In DSSCs, dye photosensitizers play a role ofabsorbing sunlight, so the photosensitizer is an important part of affecting thephotoelectric conversion efficiency of DSSCs. In order to further improve theperformance of DSSCs, the photosensitizers for DSSC were studied as follows:(1) In order to increase to the electron-donating ability of the donor part,benzimidazole groups were added to the triphenylamine framework to form doubledonors structure. The benzimidazoles triphenylamine D-D-π-A type organic dyes weredesigned and prepared, based on the structure of D-π-A type dye. The structure not onlycan reduce dye aggregates on the surface of TiO2electrode, but also can increase theutilization efficiency of light. The D-D-π-A type dyes have been applied in DSSCs andobtained relatively good photoelectric conversion efficiency. Effects of differentacceptor groups on the triphenylamine dyes for DSSCs were studied in the same time.(2) The molecular structure have a huge impact on photophysical, electrochemicalproperties of dye, so design and prepare two kinds of D-D-π-A type dyes based onimidazole and triphenylamine. The secondary donor part of the non-planar played anactive role in optimizing dye molecules, but the plane secondary donor has a negativeimpact. The dye, which the secondary donor is non-planar, got photoelectric conversion efficiency of3.13%, and N719got photoelectric conversion efficiency of5.38%underthe same conditions.(3) Design and prepare D-π-A type dyes based on non-planar imidazole group,which contrast with D-π-A type based on triphenylamine to study the electron-donatingability and photoelectric characteristics. Molecular structure of imidazole dye is verysimilar with the triphenylamine dye. Through comparative study of the two types ofdyes, imidazole dye obtained the photoelectric conversion efficiency of1.63%, which isvery close to the triphenylamine dye’s2.23%. The results show that the non-planarimidazole group is also a good electron donor in the D-π-A structure dye.