Theoretical Design And Characterization Of Double-donor Branched Organic Dyes In Dye-sensitized Solar Cells

As one of the most promising and potential solar cells in the 21 st century, DSSCs have attached much attention and attached great importance all over the world being their abundant sources, environmentally friendly and easy production. Up to now, DSSCs as the new generation organic solar cells have reached an overall conversion efficiency over 13%. The dyes reported in the laboratory was countless every year, surprising little could put in the actual production and the efficiency of DSSCs was affected by many factors, offering many possibilities for the result under the circumstances of experiment. These seriously hampered for the further expanding scale. At present, the research to sensitizers was not still comprehensive and thorough. The relationship between the molecular structure and properties are not reasonable established. Quantum chemical calculations have entered the relative mature period and become an effective means to evaluate the performance of the DSSCs device as well as a large number of theoretical work have verified its reliability. Based on the optimizing molecular structure to simulate the absorption spectra, intermolecular interaction and the nature of the charge transfer. The results were drawn and analyzed for advancing prediction via the computational method. This is effectively save a great deal of the manpower, material and financial resources.In our work, selecting various units to modify and modulate the performance of the molecules, and then to construct a D₂ A type sensitizers with providing double donors through the calculation of quantum chemistry based on reported and synthesized in experiment. Combined with a computational level, relevant parameters that effected on the conversion efficiency were characterized by adopting density functional theory?DFT? and time-dependent density functional theory?TD-DFT?. On the basis of the computed results, it can pave a new way to design sensitizers. The paper includes the following parts:1. A novel organic dye, 2D-A structure, which consisted of two separated lightharvesting moieties has been reported. First of all, based on DTP-B8 in experiment as reference dye, the UV-vis spectrum was simulated with different functionals and was screened which coincided with the experimental values. Then the related parameters which influenced J_SC and V_OC for new designed sensitizers were characterized in theory at the same method and the same basis set. Discussing the length of donor chains have an effect on photoelectric performance.2. Based on the previous work? part 1?, three series of dyes?BC-series, CB-series and CC-series? were designed and characterized for further exploring different conjugation degree and different conjugation effect have the effect on photoelectric performance.