title: 1-Alkyl-1H-imidazole-based dipolar organic compounds for dye-sensitized solar cells.
abstract: A series of donor-pi-acceptor-type organic dyes based on 1-alkyl-1H-imidazole spacers 1-5 have been developed and characterized. The two electron donors are at positions 4 and 5 of the imidazole, while the electron-accepting cyanoacrylic acid is incorporated at position 2 by a spacer-containing heteroaromatic rings, such as thiophene and thiazole. Detailed investigation on the relationship between the structure, spectral and electrochemical properties, and performance of DSSC is described here. Dye-sensitized solar cells (DSSCs) using dyes as the sensitizers exhibit good efficiencies, ranging from 3.06 to 6.35 %, which reached 42-87 % with respect to that of N719-based device (7.33 %) fabricated and measured under similar conditions. Time-dependent density functional theory (TDDFT) calculations have been performed on the dyes, and the results show that both electron donors can contribute to electron injection upon photo-excitation, either directly or indirectly by internal conversion to the lowest excited state.
authors.affiliation: Institute of Chemistry, Academia Sinica, 115 Nankang, Taipei, Taiwan.
authors.forename: Marappan
authors.initials: M
authors.lastname: Velusamy
authors.forename: Ying-Chan
authors.initials: YC
authors.lastname: Hsu
authors.forename: Jiann T
authors.initials: JT
authors.lastname: Lin
authors.forename: Che-Wei
authors.initials: CW
authors.lastname: Chang
authors.forename: Chao-Ping
authors.initials: CP
authors.lastname: Hsu