Joint electrical, photophysical, and photovoltaic studies on truxene dye-sensitized solar cells: impact of arylamine electron donors.
The judicious design of electron donors is one of the viable tactics to improve the efficiency of organic dyes for dye-sensitized solar cells (DSCs) employing outer-sphere redox couples. Herein, a hexahexyltruxene-substituted 4-(hexyloxy)-N-phenylaniline (HT-HPA) segment is constructed and employed as the electron donor in two organic push-pull dyes (M28 and M29) with high molar absorption coefficient values. Relative to its congener (C241) possessing the dihexyloxy-substituted triphenylamine electron donor, M29 exhibits red-shifted absorption as well as enhanced maximum molar absorption coefficient values. A thorough comparison with M29 and C241 demonstrates that the HT-HPA segment adequately insulates the TiO2 surface from the electrolyte, which prevents back-recombination and prolongs electron lifetime in the semiconductor. The diminishment of charge recombination not only enables attainment of strikingly high photovoltages (approaching 1 V), but also overcompensates the disadvantageous impact of lower dye-load amounts. As a result, the dye transformation from C241 to M29 brings forth an efficiency improvement from 7.3 % to 8.5 % at the 100 mW cm(-2) simulated AM1.5 conditions. Our work should shed light on the future design of more powerful push-pull organic photosensitizers for iodine-free DSCs.
Tianjin Key Laboratory of Organic Solar Cells and Photochemical, Conversion, Department of Applied Chemistry, Tianjin University of Technology, No.391 Binshui Xidao,Xiqing District Tianjin 300384 (P.R. China).
Zhihui
Z
Wang
Mao
M
Liang
He
H
Wang
Peng
P
Wang
Fangyi
F
Cheng
Zhe
Z
Sun
Xue
X
Song
D000588:Amines / Q000737:chemistry*; D000814:Aniline Compounds / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry*; D011211:Electric Power Supplies; D004563:Electrochemistry; D004579:Electron Transport; D008958:Models, Molecular; D008968:Molecular Conformation; D011758:Pyrroles / Q000737:chemistry; D012993:Solar Energy
D000588:Amines; D000814:Aniline Compounds; D004396:Coloring Agents; D011758:Pyrroles; C023650:aniline
cobalt; cyclic voltammetry; dyes/pigments; electrochemistry; solar cells