Comparative study of the photovoltaic properties of corrole- and phthalocyanine-based sensitizers for dye-sensitized solar cell (DSSC) application: a theoretical investigation

Abstract

In this paper, the photovoltaic efficiencies obtained via the electronic property study of corroles and phthalocyanines (Pcs) with metal and hydrogen atom centers by means of density functional theory (DFT, using hybrid functionals) are presented. The investigation aimed at showing the possible advantages of coordinated metal corroles over that of phthalocyanines as redox active complexes for dye-sensitized solar cell (DSSC) application. This was with a view to finding a solution to the Nigerian electricity crisis. The energy gap (δp) between the lowest unoccupied molecular orbital (LUMO) and TiO2 conduction band (CB), and their relative positions to each other revealed that most of the complexes are essentially not suitable for DSSC application. The computed δp values for the corroles (-12.4 – 7.10 eV) and the Pcs (- 5.71 – 7.92 eV) were found to be significantly higher than the recommended value (~0.40 eV), except for molecule C10 (0.9 eV) whose value appears to be the closest to 0.4 eV. It was also observed that a considerable number of the dye LUMOs showed non-alignment to the TiO2 CB edge. Based on this finding, we conclude that most of the studied complexes are structurally deficient to meet the minimum specifications to be applicable as DSSC sensitizers. However, some of the corrole (C10) and Pc (P3 and P4) molecules produced a considerably high IPCE values (in the order of 1012). The photovoltaic performance of these set of molecules could be further improved through structural modification and extension of their π-conjugation.