High-performance solar cell production by advanced plasma techniques: efficiency increase using blocking layer

Abstract

Since the introduction of this new class of photovoltaic devices by Brian O'Regan and Michael Grätzel at the beginning of the 90s, several studies have been conducted to date in order to improve the energy conversion efficiency of dye-sensitized solar cell (DSSCs). Among the changes suggested by the scientific community, the most relevant are the properties of the various components that make up the DSSC cells, such as the transparent and the conductive oxides, the dye type, the electrolyte, the counter electrode and the TiO2 structure. The research to be conducted in this project is focused on the characterization of thin films to be used in assembling of dye-sensitized solar cells, equipped with a system called "blocking layer" (BL). This system consists in inserting an ultrathin semiconductor film layer between the nanoporous TiO2 layer and the transparent conductive oxide (TCO) used in the assembly of cells. The goal is to avoid charge recombination between the electrolyte and the TCO interface, thus significantly increasing its energy efficiency. This study is a natural consequence of the works in progress by the team in which Prof. Dr. Korneli G. Grigorov (scholarship candidate) will be involved where TiOx and TiOxNy films will be deposited by plasma-assisted technique (PA-PVD), called magnetron reactive sputtering. For some of the films already made by the team, it was possible to increase by 10% the efficiency of the tested cells. The cells will be assembled using conventional geometry of two electrodes, where the counter-electrodes are manufactured using platinum films. It is noteworthy that Prof. Dr. Korneli G. Grigorov, the candidate, has great scientific experience in the processing area of materials for cold plasmas, as well as different techniques of materials characterization, which will be necessary for the successful implementation of this project. Therefore, his permanence in the team that is developing these types of photovoltaic devices will contribute in better result-oriented work with greater dynamism in the research. Finally, it is worth to emphasize that Dr. Grigorov will assist also in the co-supervision of graduate students (MS and Ph.D.), as well as he will be charged with teaching postgraduate courses at UNIFESP-ICT. (AU)