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 (VOC), and to quantify the parameters such as the light harvesting efficiency, the electron injection efficiency associated with the short-circuit photocurrent density (JSC). All the dyes showed absorbance in visible region (502-521nm) 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 (521-527nm) 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 JSC due to high driving force for electron injection. These dyes also showed high VOC (1.037-1.128eV). These results indicate that heterocyclic azo dyes will show better light to power conversion efficiency in DSSCs due high JSC and VOC. These theoretical criteria would be useful to design and fast screen other organic dyes, specifically for chemically fairly similar dyes.