Abstract
A novel series of coumarin based dyes were designed and synthesised with coumarin donor (D) moiety, various thiophene bridge (Th-π) unit and –CNCHCOOH acceptor (A). The dye sensitized solar cells' (DSSCs) performance, optical and electrochemical properties of coumarin dyes were examined systematically. Moreover, optimization calculations for the geometries of all the coumarin dyes with various Th-bridge units were studied by DFT (density functional theory). CDT-3 dye containing three Th- unit shows the highest short circuit current (Jsc = 15.14 mA/cm2) and efficiency is 6.02% under 1 sunlight (100 mW/cm2, AM1.5) illumination. The DSSCs devices with all three coumarin dyes exhibit good, long term stability up to 500hr.
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•A novel series of coumarin based dyes were design and synthesised.•Optimization geometries of coumarin dyes with various Th-bridge were studied by DFT.•CDT-3 dye containing three Th- unit shows the highest efficiency (6.02%).•DSSCs devices with all coumarin dyes exhibit good, long term stability up to 500hr.