• Vijay Singh

Articles written in Bulletin of Materials Science

• Luminescent studies of impurity doped SrS phosphors

SrS phosphors activated with Ce and Dy ions were prepared by solid-state diffusion method. Photoluminescent study was carried out on SrS : Ce, SrS : Dy and SrS : Dy, Ce. Thermoluminescence and electron spin resonance studies were also carried out on SrS : Dy phosphor. The thermoluminescence glow curve shows a peak at around 142°C. Irradiated SrS : Dy exhibits an ESR line due to a defect centre. Thermal annealing behaviour indicates that this centre correlates with the TL peak at 142°C. The centre is characterized by an isotropic g-value of 2.0039 and is assigned to a 𝐹+ centre.

• Ultraviolet B emission from a Gd$^{3+}$-doped BaAl$_2$O$_4$ powder phosphor

A BaAl$_2$O$_4$:Gd$^{3+}$ phosphor was successfully prepared using a combustion technique. An X-ray diffraction pattern was used to characterize the resultant phosphor, and the photoluminescence (PL) of the prepared BaAl$_2$O$_4$:Gd$^{3+}$ was studied. Under a 273-nm excitation, the main emission peak of the phosphor is located at 314 nm, and this is attributedto the ${}^6$P$_{7/2}\to {}^8$S$_{7/2}$ transition of Gd$^{3+}$. Electron paramagnetic resonance (EPR) spectrum appears to be U-shaped, andlines are evident at $g_{\rm eff}\sim 2.14$, 4.56 and 6.75. The PL and EPR analyses indicate the presence of Gd as Gd$^{3+}$ in this sample.

• Investigations on the ZnO- and Cr-doped ZnO powders

Among the metal–oxide nanoparticles, pure and doped zinc oxide (ZnO) has been widely studied due to their potential applications, such as electrical, thermal and optical materials. In this context, samples of undoped ZnO and Cr-dopedZnO powders were prepared using a solution-combustion route. The formation of the combustion products was confirmed by X-ray diffraction analysis. The samples were well characterized using the Fourier transform infrared spectroscopy and scanning electron microscopy techniques. In the sample, photoluminescence studies showed that ZnO could be excited at267 nm, while an ultraviolet emission centred at $\sim$383 nm was exhibited. Antibacterial-activity testing was carried out using the disc-diffusion method.

• # 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