• A MOHAMED

Articles written in Bulletin of Materials Science

• Adsorption effect of NO$_2$ on ZnO (100 nm) nanowires, leading towards reduced reverse leakage current and voltage enhancement

Here, we report the adsorption effect of NO$_2$ on ZnO (100 nm) nanowires. We have studied the effect of adsorbed NO$_2$ molecules on ZnO nanowire-based energy harvester for an exposure time of 1, 2, 3, 4, 5 and 6 h in a sealedchamber at 50 ppm which yielded piezoelectric voltage of 543.6 mV, 834.6 mV, 1.071 V, 1.78 V, 1.969 V and 2.835 V, respectively. We have thoroughly investigated the behaviour of ZnO nanowires in the presence of NO$_2$ and observed a maximum output piezoelectric voltage of 2.835 V with a power density 158.2 mW cm$^{-2}$. This is the first time that ZnO based piezoelectric energy harvester is being used for the voltage enhancement in the presence of NO$_2$. We have used vertically integrated nanowire generator (VING) structure. X-ray diffraction pattern revealed the growth orientation ofZnO nanowires were along the $c$-axis from the substrate. ZnO nanowires were grown on indium tin oxide-coated polyethylene terephthalate substrates via a hydrothermal route. Surface morphology has been examined by scanning electron microscopy images and diameter of ZnO nanowires was found to be around 100 nm. Piezoelectric voltage has been generated by the VING by applying minute external force of $\sim$50 nN. Periodic output voltage peaks were being measured by picoscope 5204.

• Effects of TiO$_2$ phase and nanostructures as photoanode on the performance of dye-sensitized solar cells

In this study, different titanium dioxide (TiO$_2$) nanostructures and phase were investigated as photoanode film for application in dye-sensitized solar cells. Rutile TiO$_2$ nanorods (NRs)-nanotrees (NTs) and TiO$_2$ NRs-microcauliflowers (MCFs) were synthesized via hydrothermal method for different time. The mixed phase of rutile-anatase film was fabricatedby applying TiO$_2$ nanoparticles paste on the synthesized TiO$_2$ NRs-NTs via squeegee method. The counter electrode film wasfabricated by spraying deposition and sputtering methods of reduced graphene oxide–multi-walled carbon nanotubes and platinum, respectively. Solar simulator measurement revealed that higher energy conversion efficiency (1.420%) and shortcircuit current density (3.584 mA cm$^{-2}$) were achieved by using rutile TiO$_2$ NRs-MCFs film. The utilization of a thick rutilefilm with microparticle structures increases dye adsorption, and thus enhances the electron excitation.

• # Bulletin of Materials Science

Volume 45, 2022
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