Benzimidazole/Pyridoimidazole-Based Organic Sensitizers for High-Performance Dye-Sensitized Solar Cells

Sumit Chaurasia; Chun-Ting Li; Mulu Berhe Desta; Jen-Shyang Ni; Jiann T Lin

doi:10.1002/asia.201700039

Benzimidazole/Pyridoimidazole-Based Organic Sensitizers for High-Performance Dye-Sensitized Solar Cells

Chem Asian J. 2017 May 4;12(9):996-1004. doi: 10.1002/asia.201700039. Epub 2017 Apr 5.

Authors

Sumit Chaurasia¹, Chun-Ting Li¹, Mulu Berhe Desta^{1

2

3

4}, Jen-Shyang Ni¹, Jiann T Lin¹

Affiliations

¹ Institute of Chemistry, Academia Sinica, Taipei, Taiwan.
² Taiwan International Graduate Program (TIGP), Sustainable Chemical Science and Technology (SCST), Academia Sinica, Taipei, Taiwan.
³ Department of Applied Chemistry, National Chiao Tung University, Hsinchu, Taiwan.
⁴ Department of Chemistry, Mekelle University, Tigray, Ethiopia.

PMID: 28300345
DOI: 10.1002/asia.201700039

Abstract

A new series of benzimidazole (BIm)-based dyes (SC32 and SC33) and pyridoimidazole-(PIm) based dyes (SC35, SC36N and SC36) were synthesized as sensitizers for dye-sensitized solar cells (DSSCs). The N-substituent and C-substituent at the BIm and PIm cores were found to be the dominating factor in determining the electronic properties of the dyes and their DSSCs performance. The efficiency of BIm-based dyes (SC35 and SC36) was found to be higher than that of the PIm-based dyes (SC32 and SC33) due to better light harvesting. The C-substituents in SC36, a 4-hexylloxybenzene and a hexyl chain, are beneficial to dark current suppression, and hence SC36 achieves the best efficiency of 7.38 % (≈85 % of N719). The two BIm dyes have better cell efficiencies than their congeners with a bithiophene entity between the BIm and the anchor due to better light harvesting of the former.

Keywords: benzimidazole derivatives; charge transfer; donor-acceptor systems; dye-sensitized solar cells; metal-free sensitizers.