Morphology-dependent space charge polarization and dielectric relaxation of CdO nanomorphotypes

Abstract

A versatile approach signifying the morphology-dependent dielectric polarization and relaxation mechanisms of cadmium oxide (CdO) nanosphere, nanoflakes and nanoparallelepiped morphotypes as a function of frequency and temperature is presented. Variation of dielectric property is observed due to the changes of space charge/interfacial polarization resulting from the variations of surface to volume ratio of nanomorphology. Accordingly, colossal dielectric constant value has been observed in CdO nanosphere having larger surface to volume ratio. The order of dielectric constant (dc) values observed for the present nanomorphologies is: dc of sphere > dc of flakes > dc of parallelepiped resembles the order of surface to volume ratios of the present morphologies respectively. The experimental data of complex impedance values are numerically fitted using theoretical models which provide the information of role of grain resistance on dielectric polarization and Cole-Cole type mechanism of dielectric relaxation process. The activation energies for electron transport are found to be 0.087 eV for spheres, 0.074 eV for flakes and 0.067 for parallelepiped nanomorphotypes of CdO. The dielectric and impedance spectroscopic analysis of the present material opens up wide scope for morphology-dependent tuning of nanomaterials for electrical applications.

α-Fe2O3 Nanoparticles Aided-Dual Conversion for Self-Powered Bio-Based Photodetector

“…As demonstrated in Figure 7 f, these photo generated electrons get quickly captured by the α-Fe 2 O 3 nanoparticles, embedded in the negative tribo-layer, that is recognized for its surpassing charge trapping property [ 39 ], confirmed by the appreciable enhancement in the dielectric properties of the PDMS based-composite owing to the insertion of α-Fe 2 O 3 nanoparticles into the pure PDMS ( Figure 7 h), while the generated holes then tend to get neutralized by the recombination with adsorbing negatively charged particles or ions from air [ 40 ]. Considering comparatively lower dielectric constant of the as prepared PDMS film ( Figure 7 h), as the general distinction of dielectric property is noticed because of the changes of space charge/interfacial polarization developing from differences in the surface to volume ratio of the presented structure morphology [ 20 , 41 , 42 , 43 ]. Hence, these trapped electrons successively, are amplified to the previously-available negative tribo-charges, resulting in an enhancement in the surface charge density of PDMS/α-Fe 2 O 3 nanocomposite film, thereby amplifying the output performance of this TENGs upon light illumination.…”

Efficient Photocatalytic and EMI Shielding Properties of CdO/ La2O3 Nanocomposites

“…The dielectric measurements are used to analyze relaxation and conductivity process in materials. The parameters such as particle size, large surface to volume ratio, defects, temperature, doping and plays a vital role in dielectric property in nanoparticles [27][28][29]. Zhao et al results observed that the increase in doping amount of lanthanum oxide with BaSrTiO3 ceramics increases the dielectric constant [30].…”

Irregular Micro-Island Arrays of CdO/CdS Composites Derived from Electrodeposited Cd for High Photoelectrochemical Performances

“…Different techniques have been proposed to synthesize CdO films such as spray pyrolysis, 13 sol-gel, 12,14 electrochemical deposition, 11,15 templateengaged approach, 16 chemical bath deposition, 17,18 and solvothermal synthesis. 19,20 To improve its PEC performance and photocatalytic activity, various micro-/nano-nanostructured CdO films have been fabricated. Those structures include nanofibers, 14 nanoboxes, 16 nanowires, 17 nanorods, 1,19 nanoflakes 20 and nanoparticles.…”

“…19,20 To improve its PEC performance and photocatalytic activity, various micro-/nano-nanostructured CdO films have been fabricated. Those structures include nanofibers, 14 nanoboxes, 16 nanowires, 17 nanorods, 1,19 nanoflakes 20 and nanoparticles. 21 CdS is also an n-type semiconductor and has a suitable bandgap (2.4 eV) for visible light absorption.…”