Quantum Chemistry Study On Regulating The Energy Conversion Performance Of Triphenylamine Dyes

Due to the controllable structure,environmentally friendly synthetic process,and low cost,organic sensitized dye have always been a hot issues in the research filed of dye-sensitized solar cells(DSSCs).In order to increase the performance of electron excitation and electron transfer in cells,15 dyes of three series have been designed.And then the geometric structure,electron distribution,energy level and spectrum of the ground and excited states of the dye had been studied,based on the density functional theory and time-dependent density functional theory.The hole-electron analysis and IFCT method have been used to quantitative analysis the electron transfer and confirm the types of electron excitation.(1)The results of RL1 series dyes show that,because of increasing the π bridge conjugation,the electron number can reach up to 0.23 and 0.27 a.u.(dye RL1-B)in the state S0 → S1 and S0 → S3,more than dye RL1,which is 0.09 and 0.05 a.u.separately.The conjugated units of RL1-O and RL1-R can also serve as additional donor.Therefore,all four dyes can decrease the intramolecular reflux phenomenon of RL1 and enhance the energy conversion efficiency.(2)The results of HB series dyes show that,the triphenyl mesitazine is not suitable as an electron donor group alone.However,it has better absorption performance in the ultraviolet-visible region with 200 ～ 700 nm.(3)The results of HBL series dyes shows that,the Y-type dyes can be constructed by adding other electron donors,especially triphenylamine on both sides,and the new dye has a lower band gap.Among them,the charge transfer of 0.154 and 0.134 a.u.occurred in the triphenylpyrazine group,it promoted the charge transfer transition of the dye molecule.The above research results provide the molecules design of dye to improve DSSCs efficiency,and guide experimental synthesis.