Theoretical Investigation On D-?-A-A Type Organic Dye Sensitizes In DSSC

In order to extend the range of its spectral absorption,based on the intensity of sunlight absorption and light-harvesting efficiency of the SD2 dye molecule in DSSC,reduce the energy difference between the highest occupied and the lowest unoccupied molecular orbital,with SD2 dye molecular electron donor and electron acceptor as the fundamental framework,the indole fragment and thiophene derivative in the prototype dye molecule were replaced by the four ?-bridges(labeled A,B,C,D,respectively)and the four auxiliary electron acceptors(labeled 1,2,3,4).For the sake of characterizing dye molecules as thoroughly as possible in DSSC,the frontier orbital energy levels,UV/Vis absorption spectra,natural bond orbital analysis,intramolecular charge transfer,charge and hole reorganization energies,parameters influencing the short-circuit current density and the open-circuit photovoltage for these 16 individual dye molecules are carried out to try to fully characterize the properties of these dye molecules.According to these computational results of physical quantities and based on the performance of these dye molecules in the above aspects,in this paper,nine of the individual dye molecules were combined with titanium dioxide cluster to calculate their geometrical structures,frontier orbital distributions,electron excitation energies,UVVis absorption spectra and the composition of the electronic transitions in chloroform solvent with polarizable continuum model.The results of these calculations show that the C-4 dye molecule has better properties in electron transfer and spectral absorption range before and after the adsorption on the titanium dioxide.