A study of optical, mechanical and electrical properties of poly(methacrylic acid)/TiO2 nanocomposite

This work is concerned with the study of the effect of titanium dioxide (TiO2) nanofillers on the optical, mechanical and electrical properties of poly(methacrylic acid) (PMAA) networks as a function of TiO2 concentration and crosslink density. The structure of the prepared samples was investigated by X-ray diffractometry (XRD) and Transmittance Electron Microscope (TEM). XRD results showed a single phase for the nanocomposites indicating that no large TiO2 aggregates in the polymer matrix. The optical properties of the prepared samples including the absorption, transmittance, energy band gap and refractive index were explored using Spectrophotometer. These measurements showed that there is a red-shift in the absorption caused by the increase of TiO2 concentration. However, the crosslink density in the polymer plays no role in changing the absorption. The energy band gap (Eg) decreases with increasing the concentration of TiO2 in the polymer matrix; whereas Eg increases with increasing the crosslink density. Moreover, the mechanical properties of PMAA/TiO2 nanocomposites by Dynamic Mechanical Analysis (DMA) showed that the viscoelasticity of PMAA decreases with adding TiO2 nanoparticles and the glass transition temperature (Tg) was also found to drop from 130 °C to 114 °C. Finally, the DC conductivity of the obtained systems was found to increase with increasing TiO2 nanoparticles in the matrix. Keywords: PMAA, TiO2, Free radical polymerization, PMAA/TiO2 nanocomposite, Optical properties, DMA technique, DC electrical conductivit

A study of the nanostructure and efficiency of solid-state dye-sensitized solar cells based on a conducting polymer

In this work the nanostructure and efficiency of solid-state dye-sensitized solar cells based on a conducting polymer have been investigated. A conducting polymer has been used as a solid-state electrolyte in the dye-sensitized solar cells. The polymer used in this study is a form of polythiophene synthesized in aqueous media. The obtained polymers were in two different structures: nanoparticles and networks. The structure of the synthesized polymers has been investigated using transmission electron microscope (TEM) and atomic force microscope (AFM). Furthermore, the optical and electrical properties of the synthesized polymers have also been considered. Solid-state dye-sensitized solar cells (SSDSCs) have been successfully constructed using these two polymers in addition to the linear poly(3-hexylthiophene) (P3HT). The photovoltaic characteristics of the assembled solar cells showed a good performance under annealing at 100 °C when using the network structure of polythiophene with a conversion power efficiency of 0.83%, while the nanoparticles polythiophene achieved 0.15% efficiency compared to 5.6 × 10−5% when using P3HT