Synthesis, characterization and photovoltaic properties of novel molecules based on triarylamine dyes

We report the synthesis, electrochemical and photovoltaic properties of triphenylamine based novel organic sensitizer, comprising donor, electron-conducting and anchoring group. Different triphenylamines were synthesized as donor unit and connected to cyano-acidic acid acceptor over vinyl group. In this work, we studied on two novel dyes (TPA2, TPA3) by attaching methyl to m-position and diphenylamine to p-position of the basic triphenylamine structure, respectively. All derivatives absorb at visible region of solar spectrum in the range of 350–632 nm. By introducing strong electron injection groups to triphenylamine ring, band gap becomes narrower while EHOMO–ELUMO levels are tuned. All current voltage (I–V) measurements were done under 100 mW/cm2 light intensity and AM 1.5 conditions. TPA3 chromophore with the lowest band gap shows the best cell performance with an efficiency (η) of 4.12%, a short-circuit photocurrent density (Isc) of 8.07 mA/cm2, an open-circuit voltage (Voc) of 714 mV and a fill factor (FF) of 0.72.