Effect of Doping and Thickness on TiO2 – MEH Multilayer Energy Gap and Absorption

Abstract

Optical and electrical properties plays an important role in physics. Namely the properties of polymers like MEH when mixed and doped with other elements are very important in solar cells and optoelectronics. The aim of this work is to produce transparent thin film using different approach and to study some optical and electrical properties of MEH doped with some compounds. The research methodology is based on finding the parameters affecting optical and electrical properties and comparing the results obtained with theoretical relations and previous studies. In this work thin films of TiO2 -MEH and TiO2 –MEH+CaSO4, TiO2 –MEH+ CuCO3 and TiO2 –MEH+La2O3 had been grown using a spin coating, cheap and simple method. The obtained deposited films were characterized using UV- visible NIR Spectrophotometer. From the collected spectra the absorbance, transmittance, as an optical properties, and electrical conductivity of the films had been deduced. The spectral analysis revealed that TiO2-MEH+CaSO4 film has high absorbance in the UV-region and low absorbance in the VIS-NIR-regions. It has low transmittance in the UV- region and high transmittance in the VIS-NIR- regions. TiO2-MEH+CuCO3 film shows high absorbance in the UV-region and high transmittance in the VIS-NIR-regions. TiO2-MEH +La2O3 has high transmission in the region 𝝀 > 600 nm. The optical energy gap of TiO2 - MEH double layer was decreased and the absorption was increased by increasing the number of them. Thus increase of TiO2 - MEH layers decreases current. Results suggest that the energy gap of TiO2 - MEH double layer can be decreased and the absorption can be increased by increasing the number of them. Thus increase of TiO2 - MEH layers decreases current. The optical energy gap of TiO2-MEH, TiO2-MEH+La2O3, TiO2-MEH+ CuCO3 and TiO2-MEH+CaSO4 takes the values 2.21, 2.15, 3.295 and 3.721 eV respectively. The various films grown in this work can be used in the agricultural industry such as greenhouse effect, In car industry such as anti-dazzling on the windscreen, beside electronics industry such as in camera lens and coating of eye glasses and in architectural industry such as poultry house and coating of windows and doors for passive heating and cooling. Thus one can conclude that the optical and electrical properties of MEH polymer is affected by the number of layers, materials type as well as its concentration. These results was explained by using quantum and classical theories of solids.