Bis(phenothiazyl-ethynylene)-Based Organic Dyes Containing Di-Anchoring Groups with Efficiency Comparable to N719 for Dye-Sensitized Solar Cells

Chi-Ho Siu; Lawrence Tien Lin Lee; Po-Yu Ho; Cheuk-Lam Ho; Tao Chen; Songwut Suramitr; Supa Hannongbua; Zhiyuan Xie; Mingdeng Wei; Wai-Yeung Wong

doi:10.1002/asia.201601427

Bis(phenothiazyl-ethynylene)-Based Organic Dyes Containing Di-Anchoring Groups with Efficiency Comparable to N719 for Dye-Sensitized Solar Cells

Chem Asian J. 2017 Feb 1;12(3):332-340. doi: 10.1002/asia.201601427. Epub 2016 Dec 27.

Authors

Chi-Ho Siu¹, Lawrence Tien Lin Lee², Po-Yu Ho^{1

3}, Cheuk-Lam Ho^{1

3}, Tao Chen^{2

4}, Songwut Suramitr⁵, Supa Hannongbua⁵, Zhiyuan Xie⁶, Mingdeng Wei⁷, Wai-Yeung Wong^{1

8

3

7}

Affiliations

¹ Institute of Molecular Functional Materials, Department of Chemistry and Institute of Advanced Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, P.R. China.
² Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong, P.R. China.
³ HKBU Institute of Research and Continuing Education, Shenzhen Virtual University Park, Shenzhen, 518057, P.R. China.
⁴ Department of Materials Science and Engineering, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui, 230026, P.R. China.
⁵ Department of Chemistry and Faculty of Science, Center of Nanotechnology, Kasetsart University, Chatuchak, Bangkok, 10900, Thailand.
⁶ State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, 5625 Renmin Street, Changchun, 130022, P.R. China.
⁷ Institute of Advanced Energy Materials, Fuzhou University, Fuzhou, Fujian, 350002, P.R. China.
⁸ Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, P.R. China.

PMID: 27897390
DOI: 10.1002/asia.201601427

Abstract

A new series of acetylene-bridged phenothiazine-based di-anchoring dyes have been synthesized, fully characterized, and used as the photoactive layer for the fabrication of conventional dye-sensitized solar cells (DSSCs). Tuning of their photophysical and electrochemical properties using different π-conjugated aromatic rings as the central bridges has been demonstrated. This molecular design strategy successfully inhibits the undesirable charge recombination and prolongs the electron lifetime significantly to improve the power conversion efficiency (η), which was proven by the detailed studies of electrochemical impedance spectroscopy (EIS) and open-circuit voltage decay (OCVD). Under a standard air mass (AM) 1.5 irradiation (100 mW cm^-2 ), the DSSC based on the dye with phenyl bridging unit exhibits the highest η of 7.44 % with open-circuit photovoltage (V_oc ) of 0.796 V, short-circuit photocurrent density (J_sc ) of 12.49 mA cm^-2 and fill factor (ff) of 0.748. This η value is comparable to that of the benchmark N719 under the same conditions.

Keywords: bridging units; charge recombination; dyes; sensitizers; solar cells.