title: Theoretical study of two-photon absorption properties and up-conversion efficiency of new symmetric organic π-conjugated molecules for photovoltaic devices.
abstract: Organic material with high intensity of two-photon absorption (TPA) induced fluorescence can be used as the frequency up-converter materials for improving efficiency of the solar cells. In this work, the organic molecular structures were designed by symmetrically grafting two elongated conjugated linkers on a conjugated core and then adding donor groups at both terminals. Fluorene derivatives as a core acceptor, phenylethynyl as the conjugated linker and diphenylamino or methyl-9H-carbozole as the donor end groups were selected. Quantum mechanical modeling techniques were applied to investigate the molecular electronic structure and properties. Absorption properties of these novel π-conjugated organic molecules were studied. The TPA cross-sections of these derivatives were calculated using few-states models, respectively. The effects of donor and acceptor groups on the TPA behaviors of these designed molecules were investigated. The up-conversion efficiency of designed molecules was also calculated.
authors.affiliation: Applied Photovoltaic Center, College of Engineering, South Dakota State University, Brookings, SD 57007, USA. Zhong.Hu@sdstate.edu
authors.forename: Zhong
authors.initials: Z
authors.lastname: Hu
authors.forename: Vedbar S
authors.initials: VS
authors.lastname: Khadka
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.forename: David W
authors.initials: DW
authors.lastname: Galipeau
authors.forename: Xingzhong
authors.initials: X
authors.lastname: Yan
mesh_terms: D000042:Absorption; D000465:Algorithms; D000814:Aniline Compounds / Q000737:chemistry; D001713:Biphenyl Compounds / Q000737:chemistry; D002227:Carbazoles / Q000737:chemistry; D003198:Computer Simulation; D004735:Energy Transfer; D005449:Fluorenes / Q000737:chemistry*; D005453:Fluorescence; D008958:Models, Molecular; D055668:Photochemical Processes; D017785:Photons; D011789:Quantum Theory; D012993:Solar Energy
chemical_list: D000814:Aniline Compounds; D001713:Biphenyl Compounds; D002227:Carbazoles; D005449:Fluorenes