Synthesis, characterization, and performance of oligothiophene cyanoacrylic acid derivatives for solar cell applications

Abstract

New dye sensitizers based on an oligothiophene cyanoacrylic acid derivative were synthesized and characterized for solar cell applications. The structures of the new dyes prepared as sensitizers based on oligothiophenes, namely5,5''-di-2-cyanoacrylic acid [2,2':5',2''-terthiophene] (dye1), [2,2':5',2''-terthiophene]-5-cyanoacrylic acid(dye2), and [2,2':5',2'':5'',2'''-quaterthiophene]-5-cyanoacrylic acid(dye3) were confirmed by elemental analysis, mass spectrometry, and 1H-NMR spectral data. The P3HT/dye2/nc-TiO2 solar cell produced the highest efficiency of 0.05% with an open circuit voltage of 0.65V compared to dyes 1 and 3 solar cells. That may have been attributed to the dyes’ molecular structure, which had different chain lengths and numbers of groups of cyanoacrylic connected to the dyes’ thiophene moiety The dark current suppressed in the P3HT/dye2/nc-TiO2 solar cells indicated the formation of the charge blocking layer, which produced an enhanced open-circuit voltage accompanied by a high onset voltage.