Influence of a D–π–A system through a linked unit of double and triple bonds in a triarylene bridge for dye-sensitised solar cells

• Published in: New journal of chemistry 2017, Vol.41 (16), p.8016-8025
• Main Authors: Huang, Rui-Yu, Chiu, Yu-Hsiang, Chang, Yu-Hsuang, Chen, Kew-Yu, Huang, Pei-Ting, Chiang, Ting-Hsuan, Chang, Yuan Jay
• Format: Article
• Language: English
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/C7NJ00413C

Herein, eight metal-free organic dyes ( YH-1–YH-8 ) containing olefin or acetylene as π-spacer linkages in a triarylene bridge were synthesised. Moreover, two dyes ( 1N-PPP and 1N-PPS ) without olefin and triple bonds as π-spacer linkages were used as references. The photophysical and electrochemical properties of the dyes were characterised, and the dyes were then used to fabricate dye-sensitised solar cells (DSSCs). We demonstrated the use of a D–π–A dipolar system by employing arylamine derivatives as an electron donor, triarylene with iterative olefin or acetylene as a π-bridge, and cyanoacrylic acid as an electron acceptor. YH-1 had olefin as a repeating unit in the triarylene bridge and exhibited broad absorption, favourable short-circuit photocurrent density ( J sc ), and favourable open-circuit voltage ( V oc ) when used in a film morphology with DCA as a coabsorbent. The optimal device exhibited a J sc of 16.23 mA cm −2 , a V oc of 650 mV, and a fill factor of 0.67, corresponding to an overall conversion efficiency of 7.08%. The photophysical properties of the DSSCs were analysed using time-dependent density functional theory with the B3LYP functional.