title: An Alkyloxyphenyl Group as a Sterically Hindered Substituent on a Triphenylamine Donor Dye for Effective Recombination Inhibition in Dye-Sensitized Solar Cells.
abstract: Recombination reactions in dye-sensitized solar cells (DSSCs) may substantially decrease the open-circuit voltage (Voc) with cobalt complex redox electrolyte. Managing steric hindrance in the dye structure is necessary to inhibit recombination reactions and thereby increase the Voc and achieve high power-conversion efficiency (PCE). New dyes with large-sized donors based on triphenylamine and modified with 4-(hexyloxy)phenyl groups were developed to identify an effective inhibitor for the recombination reaction in DSSCs with a cobalt complex redox electrolyte. The 4-(hexyloxy)phenyl tetra-adducts dye MK-123 effectively inhibited the recombination reaction, and the DSSC fabricated using this dye exhibited the highest Voc (greater than 900 mV) among the cells with the investigated dyes. However, the short-circuit current (Jsc) of the MK-123 cell was lower than that of the cell with the simple triphenylamine donor dye, MK-89. In contrast, the cell with bis-adducts dye MK-136 also exhibited an increase in its Voc without a decrease in its Jsc. Among the investigated dyes, MK-136 exhibited the highest PCE of 8.9%. The effects of the steric hindrance of the 4-(hexyloxy)phenyl substituent are discussed.
authors.affiliation: Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors.forename: Takurou N
authors.initials: TN
authors.lastname: Murakami
authors.affiliation: Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors.forename: Nagatoshi
authors.initials: N
authors.lastname: Koumura
authors.affiliation: Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Yoshida
authors.affiliation: Research Center for Photovoltaics, National Institute of Advanced Industrial Science and Technology (AIST) , 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Funaki
authors.affiliation: New Technology Research Laboratory, Sumitomo Osaka Cement Co., Ltd., 585 Toyotomi, Funabashi, Chiba 274-8601, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Takano
authors.affiliation: Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University , 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
authors.forename: Mutsumi
authors.initials: M
authors.lastname: Kimura
authors.affiliation: Division of Chemistry and Materials, Faculty of Textile Science and Technology, Shinshu University , 3-15-1 Tokida, Ueda, Nagano 386-8567, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Mori