Synthesis And Investigation Of Coumarin Sensitizers Adjusted By Steric Hindrance

Dye-sensitized solar cell can convert solar energy to electricity directly, thus attracting much attention all over the world. Compared with silicon-based solar cells, DSSCs present many advantages, such as simple assemble process and low cost. The sensitizer is the critical component of the DSSCs, taking charge of harvesting solar light and converting solar energy to electricity, which will highly affect the power conversion efficiency of the cell device.Compared with ruthenium complexes, the metal-free organic dyes have attracted more and more attentions due to their ease of molecular structure modification, low synthetic cost, and comparable efficiency. Thus, in this work, three pure organic coumarin dyes were designed and synthesized through quite straightforward process with different steric hindrance.In Chapter 1, the research background of DSSCs and development was simply introduced. Meanwhile, the structure, working mechanism, and related parameters of DSSCs were reviewed, as well as the development of different kinds of sensitizers. Then the design ideas and main research content were proposed.In Chapter 2, three coumarin dyes, coded as CS-3, CS-4, and CS-5, were synthesized by using coumarin segment as the donor, phenyl unit as the linker, and benzoic acid as the acceptor. Through moving coumarin segment from ortho-site to meta- and para-site, the steric hindrance of three dyes were adjusted.In Chapter 3, the optical and electrochemical of three dyes were measured and discussed in detail. The influence of twisted structure on absorption properties was investigated, supporting by the calculation results which was performed on Gaussian 09 program.In Chapter 4, some conclusions were summerized.