New carbazole based dyes as effective co-sensitizers for DSSCs sensitized with ruthenium(Ⅱ) complex(NCSU-10)  

作　　者：Praveen Naik Rui Su Mohamed R.Elmorsy Ahmed El-Shafei Airody Vasudeva Adhikari 

机构地区：[1]Organic Materials Laboratory,Department of Chemistry,National Institute of Technology Karnataka [2]Polymer and Color Chemistry Program,North Carolina State University

出　　处：《Journal of Energy Chemistry》2018年第2期351-360,共10页能源化学（英文版）

基　　金：Department of Textile Engineering, Chemistry and Science at North Carolina State University for the financial support

摘　　要：Herein, we report the design and synthesis of three new D-A type metal-free carbazole based dyes（S1-3）as effective co-sensitizers for dye-sensitized solar cell（DSSC） sensitized with Ru（Ⅱ） complex（NCSU-10）.In this new design, the electron rich carbazole unit was attached to three different electron withdrawing/anchoring species, viz. 4-amino benzoic acid, sulfanilic acid and barbituric acid. The dyes were characterized by spectral, photophysical and electrochemical analysis. Their optical and electrochemical parameters along with molecular geometries, optimized from DFT have been employed to apprehend the effect of the structures of these co-sensitizers on the photovoltaic performances. Further, S1-3 dyes were co-sensitized along with a well-known NCSU-10 dye in order to broaden the spectral response of the co-sensitized devices and hence improve the efficiency. The photovoltaic performance studies indicated that, the device fabricated using S1 dye as co-sensitizer with 0.2 mM of NCSU-10 exhibited improved PCE of 9.55% with JSC of 22.85 mA cm-2, VOC of 0.672 V and FF of 62.2%, whereas the DSSC fabricated with dye NCSU-10（0.2 mM） alone displayed PCE of 8.25% with JSC of 20.41 mA cm-2, VOC of 0.667 V and FF of 60.6%. Furthermore, electronic excitations simulated using time-dependent DFT, were in good agreement with the experimentally obtained results of the co-sensitizers, indicating that the exchange-correlation function and basis set utilized for predicting the spectra of the co-sensitizers are quite appropriate for the calculations. In conclusion, the results showed the potential of simple organic co-sensitizers in the development of efficient DSSCs.Herein, we report the design and synthesis of three new D-A type metal-free carbazole based dyes（S1-3）as effective co-sensitizers for dye-sensitized solar cell（DSSC） sensitized with Ru（Ⅱ） complex（NCSU-10）.In this new design, the electron rich carbazole unit was attached to three different electron withdrawing/anchoring species, viz. 4-amino benzoic acid, sulfanilic acid and barbituric acid. The dyes were characterized by spectral, photophysical and electrochemical analysis. Their optical and electrochemical parameters along with molecular geometries, optimized from DFT have been employed to apprehend the effect of the structures of these co-sensitizers on the photovoltaic performances. Further, S1-3 dyes were co-sensitized along with a well-known NCSU-10 dye in order to broaden the spectral response of the co-sensitized devices and hence improve the efficiency. The photovoltaic performance studies indicated that, the device fabricated using S1 dye as co-sensitizer with 0.2 mM of NCSU-10 exhibited improved PCE of 9.55% with JSC of 22.85 mA cm-2, VOC of 0.672 V and FF of 62.2%, whereas the DSSC fabricated with dye NCSU-10（0.2 mM） alone displayed PCE of 8.25% with JSC of 20.41 mA cm-2, VOC of 0.667 V and FF of 60.6%. Furthermore, electronic excitations simulated using time-dependent DFT, were in good agreement with the experimentally obtained results of the co-sensitizers, indicating that the exchange-correlation function and basis set utilized for predicting the spectra of the co-sensitizers are quite appropriate for the calculations. In conclusion, the results showed the potential of simple organic co-sensitizers in the development of efficient DSSCs.

关 键 词：Carbazole dyes DSSC DFF NCSU-10 Co-sensitization and photovoltaic performance 

分 类 号：TM914.4[电气工程—电力电子与电力传动]