Molecular Design Of Organic Dyes And Theoretical Study Of Key Parameters

The structure of organic dyes plays an important role in the performance of dye-sensitized solar cells,optical sensors,photocatalysis and other research fields.Theoretical calculation is one of the important ways to promote the discovery and application of new high-performance materials.Through the theoretical calculation of the key physical parameters of organic dye molecules in the photocatalytic hydrogen production and tunable laser,it can guide the subsequent experimental synthesis of organic dye molecules with excellent performance.Based on DFT and TDDFT,the energy level information,optical driving ability and optical properties of new dye molecules were studied.The work of this paper is divided into the following parts:(1)Explore the theoretical calculation model suitable for EY^2-parent structure.Based on the density functional theory(DFT)and time-dependent density functional theory(TDDFT),the calculation and screening of the exchange-related functions and basis groups in the optimization of the ground state structure of organic dyes and the calculation of excited states are carried out.Finally,the calculated results obtained by the combination of function LSDA and basis set 6-311G+(d,p)are most consistent with the experimental values,which provides a theoretical guarantee for the design and characterization of new organic dye molecules.(2)Based on the parent prototype EY^2-1 dye,the dye molecular groups were systematically designed at R1and R2 positions,a series of organic dyes were obtained.By studying their molecular structure and energy level,Reduction potential and reduction driving force,the results show that EY^2-11 has a more negative reduction potential and a stronger reduction driving force,thereby effectively improving the efficiency of light-driven catalytic hydrogen production.(3)Based on LD1,the molecular structure,energy level,electron orbit and absorption spectrum of LD1-4 and LA2-5 were studied theoretically by modifying the donor and acceptor structures.The results show that compared with LD1,the position of the largest absorption peak of LA3 has a red shift of 188nm,a better band gap and electron delocalization.It is beneficial to broaden the adjustable range of dye laser and improve the light absorption ability of dye molecules.(4)Based on LA3,new organic dyes LA4-LA5?LU1-5?LV1-4?LI1-4 were designed by modifying the donor,acceptor and?-conjugated bridge structure.The results show that compared with LA3,LI3 has a wider absorption range(covering the whole visible absorption spectrum from 380-750nm)and a higher molar extinction coefficient(up to 132%),a more suitable electron orbit and a better electron delocalization.Therefore,it can be considered theoretically that LI3 is a potentially efficient organic dye molecule in dye lasers.