Tuning the HOMO and LUMO energy levels of dye sensitizers with electron-accepting capability and electron-drawing capability of substituents to optimize the efficiency of dye-sensitized solar cells: Approach of theoretical

Abstract

In this work, for first time, TiO2 nanoparticles (TiO2 NPs) was synthesized by Dodecan-1,12-bis (triethylammoniumbromide) bolaform surfactant as template with sol-gel method. Then, prepared TiO2 NPs was crystalized in anatase phase and properties of this TiO2 NPs were compared with the properties of commercial TiO2 (P25). BET result demonstrated that compare to P25, synthesized TiO2 NPs has a very higher surface area. Both TiO2 were sensitized with N719 dye and then they used as photoanode to compare their results. The results displayed that although synthesized TiO2 NPs has lower efficiency in solar cell, it has a better fill factor compared to the P25. Also, the properties of TiO2 NPs in anatase phase in bulk and at (1 0 1) surface have been investigated by using quantum espresso (QE) package. The Band Structure and density of State (DOS) TiO2 NPs in bulk and at (1 0 1) surface have been studied. What is interesting in this article is that Dodecan-1,12-bis (triethylammoniumbromide) bolaform surfactant has been used as a templet by sol-gel method, which has increased the level of synthesized TiO2, resulting in the absorption of pigment on TiO2 increases. Absorption of more pigment on TiO2 can reduce dark stream recombination.