• M SHOAIB

Articles written in Bulletin of Materials Science

• A first-principles investigation on electronic, optical and thermoelectric properties of La$_2$Pd$_2$O$_5$ compound

A number of ternary-semiconductor oxides have shown promise for potential applications in catalysis, thermoelectricity, optoelectronics and electrochemistry. In this work, the thermoelectric and optoelectronic properties of La$_2$Pd$_2$O$_5$ compound are studied by the full-potential linearized augmented plane wave method based on density functional theory. The electronic band structure shows an indirect band gap of 1.342 eV for La$_2$Pd$_2$O$_5$. Partial and total density of states indicate strong hybridization among different electronic orbitals. The upper part of the valence band is dominated by the Pd-d and O-p states, while the lower conduction band originates mainly from the Pd-d state. Dielectric functions including the imaginary and real parts, along with other optical constants, such as absorption coefficient, energy loss function, reflectivity and refractive index, have been reported for the first time. Thermoelectric properties, including electrical and thermal conductivity, Seebeck coefficient and power factor with variation in temperature are also presented and discussed using semi-classical Boltzmann transport theory for the first time for La$_2$Pd$_2$O$_5$. It has been found that La$_2$Pd$_2$O$_5$ has attractive optoelectronic and thermal properties that can make it a suitable candidate for efficient thermoelectric and optoelectronic device applications.

• Enhanced dielectric and thermal performance by fabricating coalesced network of alumina trihydrate/boron nitride in silicone rubber for electrical insulation

Silicone rubber filled with micron-alumina trihydrate (ATH) is a substantially used composite material for high voltage outdoor insulators. This article investigates the effect of nano-boron nitride (BN) addition on the dielectric,thermal stability and thermal conductivity of solely micron-ATH-filled silicone rubber by fabricating coalesced network of particles. Micron-ATH/nano-BN-filled hybrid silicone rubber composites are fabricated with a ratio of 30/0 wt%(ATH30), 29/1 wt% (ATBN1), 27/3 wt% (ATBN3), 25/5 wt% (ATBN5) and 23/7 wt% (ATBN7) using mechanical mixing and water bath sonication techniques. Results suggest that the hybrid batch of silicone rubber composites (ATBN) possess lower permittivity, dielectric loss, enhanced thermal stability and thermal conductivity relative to ATH30. ATBN1 offers low permittivity and dielectric loss values of 3.64 and 0.0086 at 1000 Hz relative to 3.87 and 0.0224 ofATH30, respectively. As far as thermal properties are concerned, ATBN5 emerges as the most promising candidate for electrical insulation with 31 and 200$^ {\circ}$C higher temperatures for 10 and 15% mass loss, whilst it has shown 20% higher thermal conductivity than ATH30.

• Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020