Benzotriazole-based dyes containing a low band gap for dye-sensitised solar cells: a theoretical study

Abstract

In this study, we investigated a series of metal-free benzotriazole-based organic dyes. The geometries, electronic properties, light harvesting efficiency, and electronic absorption spectra of these dyes were studied using the density functional theory and time-dependent density functional theory. The optimised geometries indicate that these dyes are non-planar and thereby effectively inhibit close intermolecular π–π aggregation. The band gap of these dyes ensures a positive effect on the process of electron injection and dye regeneration. The band gap trend corroborates well with the predicted spectra data. Our theoretical calculations reveal that the designed metal-free organic dyes can be used as potential sensitisers for solar cells compared to the best known organic sensitiser (Y123) to date.

Keywords:

• dye-sensitised solar cells (DSSCs)
• solar cells
• benzotriazole-based dye
• organic dye
• density functional theory
• time-dependent density functional theory

Additional information

Funding

This work was supported by NRF [grant number 2007-0056343] funded by MEST, Republic of Korea (MEST). The authors would like to acknowledge support from the KISTI supercomputing center through the strategic support program for supercomputing application research [No. KSC–2012-C2-74].