Investigation of low-cost magnesium stannate transparent conductive oxide layer: optical, structural and electrical properties and photovoltaic applications

Abstract

In this research investigation we reveal the development of Magnesium Tin Oxide (MTO) as Transparent Conductive Oxide (TCO) material. It is the best replacement for the existing TCO materials. In the present work, Tin (II) Chloride and Magnesium Acetate are (MA: SC) taken in different ratios (0.1M: 0.1 M- S1C, 0.1M: 0.2M- S2C, 0.1M: 0.3M-S3C, 0.1M: 0.4M-S4C, 0.1M: 0.5M-S5C) and the prepared solution is coated at the deposition temperature of 400° C by NSP technique. The deposited thin films are then annealed at a very high temperature of 500°C for three hours. A structural study explains that the prepared films exhibiting a strong diffraction peak, corresponding to the plane (105) magnesium tin oxide of rhombohedral structure. It is noted that the value of thickness is varied from 210nm to 480 nm when the molar concentration of Tin (II) chloride increases from 0.1M to 0.5M. The maximum transmittance obtained is more than 80% with a wider band gap of 3.89eV. FE-SEM shows improved crystallinity, development of grain size and the attainment of uniformity in grain distribution after annealing. From EDAX analysis, it is noted that when the concentration of Tin (II) Chloride as well as annealing temperature increases, the presence of unwanted elements is reduced and hence the purity is improved. FTIR result shows the presence of functional groups present in the prepared MTO thin films. From the studies of Hall Effect measurements, the value of the resistivity is measured and it is in the order of 10−3(Ω cm). Photo-anodes and counter electrodes of DSSC are prepared with MTO as TCO substrate, and the cell efficiency is measured. The discussions explain that DSSC constructed with platinum coated on MTO (S5C) as counter electrode and TiO2 coated on MTO (S5C) as photo anode shows a better power conversion efficiency of 3.28% than the rest of the other cells.