Effect of novel anchoring groups on the electronic and optical properties of water-splitting metal-free dye molecules: A first-principles investigation

Abstract

Dye-sensitized water splitting systems are considered to be a viable alternative to split the water and provide the clean energy. However, the current water-splitting dyes are limited mainly to those possessing the carboxylic acid anchoring group, which restraints the materials selection process. In this manuscript, we perform first principles calculations to explore new anchoring groups and understand the effects of novel anchoring groups via on the electronic and optical properties of the water-splitting dye molecules, based on an experimentally-validated water-splitting metal-free organic dye that possesses a carboxylic acid anchoring group. We find that the alternative anchoring groups offer comparable electronic and optical properties in the dyes compared with the carboxylic acid group, and address the importance of considering the novel anchoring groups in the design of the water-splitting devices. We expect that the performance of the water-splitting devices could be further improved by finding suitable anchoring groups that present superior light-absorbing and charge transfer properties in the water-splitting photoelectrodes.