Bi-anchoring organic sensitizers of type D-(π-A)2 comprising thiophene-2-acetonitrile as π-spacer and malonic acid as electron acceptor for dye sensitized solar cell applications

• Two new bi-anchoring organic sensitizers of type D-(π-A)2 were synthesized and characterized.
• Carbazole based device exhibits high current conversion efficiency (η = 4.7%) under AM 1.5 illumination.
• More negative LUMO energy levels provides sufficient driving force for the electron injection into TiO2.

Two new bi-anchoring organic sensitizers of type D-(π-A)2 comprising the identical π-spacer (thiophene-2-acetonitrile) and electron acceptor (malonic acid) but different aryl amine as electron donors (diphenylamine and carbazole) were synthesized, characterized and fabricated metal free dye-sensitized solar cell devices. The intra molecular charge transfer property and electrochemical property of these dyes were investigated by molecular absorption, emission, cyclic voltammetric experiments and in addition, quantum chemical calculation studies were performed to provide sufficient driving force for the electron injection into the conduction band of TiO2 which leads to efficient charge collection. Among the fabricated devices, carbazole based device exhibits high current conversion efficiency (η = 4.7%) with a short circuit current density (JSC) 15.3 mA/cm2, an open circuit photo voltage (VOC) of 0.59 V and a fill factor of 0.44 under AM 1.5 illumination (85 mW/cm2) compared to diphenylamine based device.

Two new bi-anchoring organic sensitizers of type D-(π-A)2 comprising the identical π-spacer as thiophene-2-acetonitrile, electron acceptor as malonic acid but different aryl amine as electron donors (diphenylamine and carbazole) were synthesized for dye sensitized solar cell fabrication. Among two dyes, carbazole based device exhibits high current conversion efficiency (η = 4.7%) under AM 1.5 illumination (85 mW cm−2) compared to diphenylamine based device.Figure optionsDownload as PowerPoint slide