Heterocyclic azo dyes for dye sensitized solar cells: A quantum chemical study

This study was carried out to design heterocyclic azo dyes for dye sensitized solar cells. Quantum chemical calculations were performed to determine the open-circuit photovoltage (V-OC), and to quantify the parameters such as the light harvesting efficiency, the electron injection efficiency associated with the short-circuit photocurrent density (J(SC)). All the dyes showed absorbance in visible region (502-521 nm) with high oscillator strength (F) (0.473-0.961) and light harvesting efficiency (LHE) (0.663-0.891). After binding to titanium oxide, all dye showed slightly red-shifted absorption (521-527 nm) with improved oscillator strength (f) (0.573-0.991) and light harvesting efficiency (LHE) (0.733-0.898). There is high probability that these dyes will show larger J(SC) due to high driving force for electron injection. These dyes also showed high V-OC (1.037-1.128 eV). These results indicate that heterocyclic azo dyes will show better light to power conversion efficiency in DSSCs due high J(SC) and V-OC. These theoretical criteria would be useful to design and fast screen other organic dyes, specifically for chemically fairly similar dyes. (C) 2015 Elsevier B.V. All rights reserved.