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Abstract: Two new star-shaped difluoroboron β-diketonate complexes (TBC) 3 Ph and (TBF) 3 Ph, in which the terminal groups of triphenylamine functionalized difluoroboron β-diketonates were bridged by carbazole or fluorene to the core of 1,3,5-benzene, have been synthesized. It was found that they gave high molar extinction coefficients, meaning strong light-harvesting ability, and emitted intense yellow light with fluorescence quantum yields (Φ F) of 0.73 and 0.67 for (TBC) 3 Ph and (TBF) 3 Ph, respectively, in toluene as well as red light in solid states with Φ F of 0.36 and 0.27, respectively. The electrochemical behaviors suggested that they had considerably higher electron affinities than tris(8-hydroxyquinoline)aluminum (AlQ3), which indicated that they could be used as electron-transporting materials besides emitting materials. [Copyright &y& Elsevier]

Abstract: Three new triphenylamine-based dyes with Y-shaped conformation bearing triphenylamino-vinyl, 10-octyl-10H-phenothiazine-vinyl and 9-octyl-9H-carbazole-vinyl as arms (TT, TP, and TC) have been synthesized. From electrochemical investigations it is found that they can be employed in DSSCs due to the balanced HOMO and LUMO energy levels. Notably, the photo-to-electrical conversion efficiency of the DSSCs sensitized with branched TT, TP, and TC reach 5.12%, 4.84%, and 3.63%, which are higher than that sensitized with T (2.79%), and the DSSC sensitized with TT shows higher IPCE response and better photovoltaic performances (J sc=12.37mA/cm2, V oc=0.72V and ff=0.58) than others. These results reveal that the introduction of branched Y-shaped extended π-conjugated donors to D-π-A dyes cannot only enlarge the spectral response range, but also suppress the molecular aggregation on TiO2 films to a certain extent, which would enhance the performance of DSSCs. [Copyright &y& Elsevier]

Abstract: We have synthesized a series of new dipolar organic dyes Bn (n=0, 1, 2) employing triarylamine as the electron-donor, 2-cyanoacrylic acid as the electron-acceptor, and fluorenevinylene as the conjugated bridge, which were used as sensitizers in dye-sensitized solar cells. It is found that the solar-energy-to-electricity conversion efficiencies of the prepared DSSCs are in the range of 2.79–5.56%, which reach 35–70% of a standard device based on N719 fabricated and measured under the same conditions. The DSSC sensitized with B1 with balanced length of conjugated bridge shows the highest photo-to-electrical energy conversion efficiency and the open-circuit photovoltage (V oc) of 0.86 V. [Copyright &y& Elsevier]