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Indexed by:期刊论文

Date of Publication:2022-07-01

Journal:Acta Physica-Chimica Sinica

Affiliation of Author(s):物理学院

Volume:29

Issue:2

Page Number:255-262

ISSN No.:1000-6818

Key Words:"Dye-sensitized solar cell; Organic photosensitizer; Conjugated bridge; Density functional theory; Methenyl chain; Furan ring; Thiophene ring"

CN No.:11-1892/O6

Abstract:Taking dye D5 molecules as the prototype, different types and different elemental quantities of conjugate pi bridge was used to design D-pi-A organic molecules. Density functional theory (DFT) and timedependent density functional theory (TDDFT) were adopted to simulate the geometric structures, molecular orbital energy levels, and UV-Vis absorption spectra of the molecules, with the aim of finding conjugate pi bridge in the sensitizer molecules for dye-sensitized solar cells (DSSCs). The absorption spectra of the molecules usingmethenyl chains,furan ringsorthiophene rings,methenyl chains and furan rings, ormethenyl chains and thiophene ringsas conjugate pi bridge showed a gradually increasing red-shifting trend. With increases in the number of conjugate pi bridge elements, the absorption spectrum showed an intense red-shift, which weakened gradually; under the same conditions, the lowest unoccupied molecular orbital (LUMO) energy level of the molecules gradually decreased, and the highest occupied molecular orbital (HOMO) energy level gradually increased. The HOMO energy levels of the molecules with threemethenyl chain and furan ringormethenyl chain and thiophene ringelements as conjugate pi bridge were higher than the energy level of the redox electrolyte; in polar solutions, the HOMO energy levels of the molecules adopting twomethenyl chain and furan ringormethenyl chain and thiophene ringelements as conjugate pi bridge were higher than the energy level of the redox electrolyte.The absorption spectra of the organic sensitizer molecules with severalmethenyl chain and furan ringor methenyl chain and thiophene ringelements as conjugate pi bridge showed an intense red-shift. These results showed that for DSSCs sensitizer molecules, it is not necessary to have many conjugate pi bridge elements; one to two elements is typically enough.

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