Theoretical Exploration And Molecular Design Toward Sensitizer Of Dye-sensitized Solar Cell

Dye-sensitized solar cell is one new kind of solar cell invented in the1991, whichis widely believed to be the powerful weapon to solve the challenge of energy crisis.Among the research of DSSC, the exploration toward sensitizer plays the central role.To explore the nature of the difference of various series of sensitizers, DensityFunctional Theory (DFT), Time-depended Density Functional Theory (TDDFT) andwave function analysis are employed during the research.The geometry, the electronic structure, the polarity, absorption spectra andcapability of denoting electron of sensitizers are indicated to influence the finalperformance of dye sensitized solar cell by computation. Porphyrin-based sensitizershould have reasonable geometry to fulfill the requirements of absorption of verticalmonolayer. The energy gap between excited state and ground state imposes hugeinfluence toward the absorption spectra. The smaller the energy gap of sensitizer is,the wider spectral of solar energy can be utilized. Highest occupied molecular orbital(HOMO) should distribute on the donor group, meanwhile the lowest unoccupiedmolecular orbital (LUMO) should distribute on the electron-withdrawing group. Thisreasonable distribution of frontier orbital is the prerequisite of good efficiency ofDSSC. The dipole moment on the vertical direction of semiconductor for sensitizerenjoys positive correlation with the open-circuit voltage. The light harvestingefficiency (LHE) determined by the strengthen factor of transmission also enjoyspositive correlation with short-circuit currency. By the exploration toward the currentmolecules, a quantitative model to describe the proportionality relationship betweencapability of donating electron on the ring of porphyrin and efficiency of DSSC hasbeen established.Molecular modeling is also employed to design new sensitizers to offset theintrinsic defect of experimental ones.