Abstract
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 -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 (384-542nm) 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 -spacer. Copyright (c) 2015 John Wiley & Sons, Ltd.