Ag Reflectors: An Effective Approach to Improve Light Harvesting in Dye Sensitized Solar Cells

Abstract

High-performing and commercially viable dye sensitized solar cells (DSSCs), operable under indirect sunlight illumination, exhibit great potential among current photovoltaic technologies, however, have smaller light absorption coefficients that hinder their usefulness. In this article, we have focussed on enhancing the light-harvesting of DSSCs by using silver nanoparticles thin films to improve the light absorption of N719 dye molecules loaded over the active layer of mesoporous TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> (m-TiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ). The Ag nanoparticles thin films acted as reflectors in the fabrication of DSSCs, which resulted in a power conversion efficiency of 6.65% compared to the 5.61% of the standard configuration cells. The effect is ascribed to the increased light absorption ability of DSSCs given the improved reflectivity of the counter electrode through Ag reflectors, resulting in the reabsorption of reflected light by the sensitized photoanodes. The results were further supported by the reduced resistances at different interfacial layers in the DSSCs, as measured by electrochemical impedance spectroscopy, thus indicating improved charge transfer kinetics. This article provides insight into the possibility of exploiting Ag nanoparticles in reflectors for improving light harvesting in the PV devices realm.