Effects of π-linker, anchoring group and capped carbazole at meso-substituted zinc-porphyrins on conversion efficiency of DSSCs

A series of zinc-porphyrin based sensitizers, F1-F6, has been studied using theoretical calculations to investigate their performances in dye-sensitized solar cells (DSSCs). Three effects; (i) pi-Linker, (ii) anchoring group and (ii) capped carbazole at meso-substituted porphyrin core on the energy conversion efficiency of the DSSCs were evaluated. The results reveal that the increased conjugation length in pi-linker and use of cyanoacrylic acid as an anchoring group can enhance charge transfer ability from donor to acceptor group and further to TiO2 which leads to increasing of the current density of the devices. Capped carbazole unit does not significantly affect the electronic properties of the dyes but crucially helps in suppressing aggregation of the dyes on the TiO2 surface, then leads to higher conversion efficiency of the device. Therefore, we predict that F6 designed by taking advantages of all positive key parameters would be a promising sensitizer for higher efficient photovoltaic cell. (C) 2015 Elsevier Ltd. All rights reserved.