• NASTARAN RIAHI-NOORI

Articles written in Bulletin of Materials Science

• Effect of chemical composition and alumina content on structure and properties of ceramic insulators

In the present work, six electrical porcelain compositions with different amount of alumina and silica have been prepared and fired in an industrial furnace at 1300°C. Density, porosity, bending strength and electrical strength were measured in the samples. In order to find a relationship between properties and sample microstructures, samples were analyzed by scanning electron microscope (SEM) and x-ray diffraction (XRD) techniques. The results showed that, with chemical composition of 53.5 wt.% SiO2 and 37.5 wt.% alumina, highest electrical strength of 21.97 kV/mm was achieved in fabricated electrical porcelains. Increasing amount of alumina up to 30 wt.% decreases quartz and cristobalite phases, but increases corundum phase 3 to 5 times. SEM observation revealed that dense particles and uniform distribution of long and thin needle shaped mullite are predominant in sample microstructures with highest electrical strength.

• Investigation of the effect of MAI and PbI$_2$ concentrations on the properties of perovskite solar cells

Here, the effect of perovskites layer quality on the performance of compact-TiO$_2$/mesoporous-TiO$_2$/CH$_3$NH$_3$PbI$_3$/carbon solar cells was investigated. Different perovskite layers were prepared by varying concentrationsof PbI$_2$ and CH$_3$NH$_3$I, while reaction temperature and dipping time were fixed. The range of concentrations for PbI$_2$ and methylammonium iodide (MAI) were 1–1.4 M and 6–10 mg ml$^{−1}$, respectively. Fabricated perovskite layers were first coated by carbon electrodes (5-layer) and then, the champion one was coated by Spiro-OMeTAD (as a hole transport material) andAu-evaporated layer as a cathode (6-layer). Fabricated films were fully characterized by field emission scanning electron microscopy, X-ray diffraction analysis, UV–Vis spectroscopy and photoluminescence spectrum. Photovoltaic properties were measured under AM 1.5. Output currents of 5-layer cells were in the range of 228–476 $\mu$A, of which the highest one was obtained by using 1.2M PbI$_2$ and 8 mg ml$^{−1}$ MAI. Ultimately, the maximum power conversion efficiency of 9.1% was obtained with 6-layer cell.

• # 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