Effect of thiophene-based π-spacers on N-arylphenothiazine dyes for dye-sensitized solar cells. (February 2021)

• Record Type: Journal Article
• Authors: Almenningen, David Moe; Hansen, Henrik Erring; Vold, Martin Furru; Buene, Audun Formo; Venkatraman, Vishwesh; Sunde, Svein; Hoff, Bård Helge; Gautun, Odd Reidar
• Is Part Of: Dyes and pigments. Volume 185(2021)Part B
• Publication Date: 2021-02
• Subjects: Oligothiophene -- Phenothiazine dye -- Dye-sensitized solar cell -- π-spacer -- Electrochemical impedance spectroscopy; Dyes and dyeing -- Periodicals; Pigments -- Periodicals; 667.2
• DOI: 10.1016/j.dyepig.2020.108951
• Languages: English
• ISSNs: 0143-7208

Abstract

Abstract: To study the effect of π-spacers on dye performance in DSSC, five novel phenothiazine dyes have been prepared where the number of successive thiophenes in the π-spacer was increased from zero to four. Additionally, a dye bearing thieno[3, 2- b ]thiophene was synthesized, and compared to its unfused bithiophene analogue. When the number of thiophenes were two or more the light absorption properties was significantly better in the region 400–550 nm compared to the dye without a π-spacer. DSSC device testing revealed that the reference dye without a π-spacer gave the best overall performance producing a power conversion efficiency of 5.7% ( J SC = 10.1 mA cm −2, V OC = 0.83 V, FF = 0.68), attributed to the superior V OC of this dye. The incorporation of one and two thiophenes resulted in a similar performance as the reference, while incorporation of larger oligothiophenes proved to be deleterious to DSSC-performance. Electrochemical impedance spectroscopy indicates that the voltage drops and performance loss associated with these dyes are due to more facile recombination. Graphical abstract: Image 1 Highlights: Six novel phenothiazine dyes have been synthesized and characterized for DSSC. A systematic study on increasing number of thiophenes in the π-spacer was investigated. Best DSSC efficiency was observed for no thiophene π-spacer. Three or four thiophenes were detrimental to DSSC performance.