Synthesis, optical and electrochemical properties of new thieno[2,3-b]indole-based dyes

Three new push-pull dyes consisting of a thieno[2,3-b]indole ring system as an electron donor, thiophene spacer as a π-bridge, and electron-withdrawing moieties such as 2-methylene malonitrile, 2-methylene-1Hindene-1,3(2H)-dione, and 2-(2-methylene-3-oxo-2,3-dihydro-1H-inden-1-ylidene)malononitrile, have been synthesized and studied for their application in organic electronics devices.Investigation of their optical and electrochemical properties reveal that these compounds possess narrow band gaps (1.7-2 eV) and an effective absorption in the visible spectral range (440-740 nm).Therefore, these chromophores can be regarded as promising light-harvesting materials.