Titania Nanorods Embedded with 2-Bromo-3-(methylamino)naphthalene-1,4-dione for Dye-Sensitized Solar Cells

Abstract

In a recent study, TiO 2 nanorod electrodes were prepared by the hydrothermal approach followed by calcination at various temperatures from 300 to 600 °C. The effects of calcination temperature on the morphological and structural properties were investigated. The novel analogue of aminonaphthoquinone(2R-(nalkylamino)-1,4-naphthoquinone) photosensitizer, viz. BrA1, 2bromo-3-(methylamino)naphthalene-1,4-dione was synthesized from 2,3-dibromonaphthalene-1,4-dione. X-ray crystallographic data collection and refinement confirm that BrA1 crystallizes in the triclinic space group P1̅ . After loading BrA1, the photosensitizer on the annealed TiO 2 nanorod (TiO 2 NR) electrodes, the optical properties of the photoanodes showed broadbands in each of the UV and visible regions, which are attributed to the π →π* and n → π* charge-transfer transitions, respectively. The dye-sensitized solar cell (DSSC) system was formed by loading the BrA1 photosensitizer on TiO 2 NR. The electrochemical impedance spectroscopy (EIS) analyses confirm that calcination temperature improves the charge transportation by lowering the resistance path during the photovoltaic process in TiO 2 NR (400 °C) photoanode-based DSSCs due to the sufficient photosensitizer adsorption and fast electron injection. Due to the effective light harvesting by the BrA1 photosensitizer and charge transport through the TiO 2 nanorod, the power conversion efficiencies (PCE) of the TiO 2 NR (400 °C/BrA1-based) DSSCs were improved for 2-bromo-3-(methylamino)naphthalene-1,4-dione.