Effect of thiophene rings on UV/visible spectra and non-linear optical (NLO) properties of triphenylamine based dyes: a quantum chemical perspective

In this study, density functional theory (DFT) and time-dependent DFT (TD-DFT) theory are use to shed light on how the number of thiophene rings in π-conjugated system influence the absorption spectra and non-linear optical (NLO) properties of dyes. The results of theoretical computation show that the absorption spectra are gradually broadened and red-shifted (384–542 nm) with increasing number of thiophene units. The theoretical examination on non-linear optical properties was performed on the key parameters of polarizabilty and hyperpolarizability. A remarkable increase in non-linear optical response was observed on insertion of thiophene rings in π-spacer.