Optical Characterization of a Single Quantum Emitter Based on Vanadium Phthalocyanine Molecules

Single quantum emitters play a fundamental role in the development of quantum technologies such as quantum repeaters, and quantum information processing. Isolating individual molecules with stable optical emission is an essential step for these applications, specially for those molecules that present large coherence times at room temperature. Among them, vanadium-oxide phthalocyanine (VOPc) molecules stand out as promising candidates due to their large coherence times measured in ensemble. However, the optical properties of individual molecules have not yet been reported. Here we show that single VOPc molecules with stable optical properties at room temperature can be isolated. We find that the optical response of the molecule under laser illumination of different polarization agrees well with a system having pyramidal C$_{4v}$ symmetry. Furthermore, the molecule reveals a non-radiative transition rate that depends on the excitation wavelength when its lifetime is interrogated. We provide theoretical calculations that support our experimental findings and provide insight to the role of phonons and internal electronic structure of the molecule. These results demonstrate that this single paramagnetic molecule can function as a single quantum emitter while displaying optical stability under ambient conditions to have their intrinsic properties investigated

Magnetic and electrical properties of manganese and cadmium co-substituted lithium ferrites

Manganese and cadmium co-substituted lithium ferrite having the general formulae Li0.35Cd0.3MnxFe2.35−xO4 + 0.10 wt% Bi2O3 with x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0 has been prepared by standard ceramic technique. M–H curves of all samples have been determined by using vibrating sample magnetometer (VSM). The highest saturation magnetization 79 emu/g is observed in Li0.35Cd0.3Fe2.35O4 (Mn = 0) and it decreases with increase in manganese content in the compound. It is observed that the value of initial permeability increases to maximum value ∼230 for Mn = 0.4 and then decreases with further increase in Mn contents. The dc resistivity of all samples is found in the range of 107 Ω cm

Study of Defect-Induced Chemical Modifications in Spinel Zinc-Ferrites Nanostructures by In-Depth XPS Investigation

Spinel zinc ferrite nanomaterials with exceptional physiochemical properties are potential candidates for various applications in the energy and environmental fields. Their properties can be tailored using several methods to widen their applications. The chemical combustion approach was followed to prepare the spinel zinc ferrite nanomaterials, which were then subjected to thermal treatment at a fixed temperature. Thermal heat treatment at a fixed temperature was used to evaluate the phase and morphological characteristics of the prepared spinel zinc−ferrite nanocomposites. Various techniques were employed to examine the samples, including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). XPS and X-ray−induced Auger electron spectroscopy were used to extensively examine the surface characteristics of the zinc−ferrite. To study the actual chemical states of the synthesized spinel zinc ferrite nanomaterials and the defects created during the thermal treatment, an extensive investigation of the kinetic energy of the X-ray−induced Zn L3M45M45 and Fe L3M45M45 was conducted. Finally, a detailed analysis of the Wagner plot using the modified Auger parameter was performed to verify the exact chemical states of Zn and Fe. Thus, the findings of the investigation show that XPS is a promising and powerful technique to study the composition and chemical states of spinel zinc ferrites, providing an understanding of changes in their properties for functional applications

Ferrites as an alternative source of renewable energy for hydroelectric cell

There are many conventional ways of producing energy at large scales such as fossil fuels, hydroelectric power station, wind energy, solar cell plants, marine energy, etc., but most of these require bulky plantation, huge manpower, wide land occupation and are non-portable and expensive to handle too. In the twenty-first century, there is still a huge gap between worldwide energy supply and its demand. The advances in the technology sector have also increased the consumption of energy, but the sources of generating the renewable energy remain limited. In order to account for these problems in recent years, several methods have been adopted and a significant research in this direction has been made by the invention of the hydroelectric cell by Dr. R. K. Kotnala’s group in 2016. Instead of using the magnetic character in the ferrite nanostructures, these nanomaterials were first time effectively exploited for direct energy harvesting application by using their capability to dissociate the absorbed water molecules on its porous surface. This allows the production of ions, which is then followed by the charge transfer of hydronium, hydroxyl and hydrogen ions between the electrodes of the ferrite nanostructures and results in the generation of an electric current across the circuit. The concept of the hydroelectric cell is new, and these cells are easily portable, inexpensive, biodegradable and eco-friendly in nature. This chapter provides an insight on the concept of spinel ferrite nanostructures for the application in the hydroelectric cell.Instituto de Física (IF

Cu nanoclusters in ion exchanged soda-lime glass : study of SPR and nonlinear optical behavior for photonics

Please read abstract in the article.The South African Research Chairs Initiative of the Department of Science and Technology (84415) and the National Research Foundation (Prof. R.E. Kroon, Grant Number 93214) for photoluminescence measurements.http://www.elsevier.com/locate/apmt2020-06-01hj2019Physic

Cobalt doping induced shape transformation and its effect on luminescence in zinc oxide rod-like nanostructures

The structural and optical propertie of semiconducting oxide nanomaterials offer several possibilities for applications in photocatalytic activities, solar cells and gas sensing owing to their reduced dimensions and large surface/volume ratios as compared to their bulk counterparts. In this study, undoped and Co doped ZnO nanostructures were prepared by a chemical co-precipitation method. The XRD patterns confirmed that all the samples were crystalline with a wurtzite hexagonal phase without forming any additional phases. A drastic change in the morphology from the transformation of spherically shaped nanoparticles (NP’s) to rod-like shaped NP’s after Co doping was revealed by SEM and TEM micrographs. Raman spectra confirmed the presence of a defect associated peak in Co doped ZnO NP’s. A direct correlation of change in surface morphology after Co doping was observed with PL emission, where near band edge emission in undoped ZnO was transformed into strong blue defect emission