Lehlohonolo F. Koao; Setumo V. Motloung; Tshwafo E. Motaung
Abstract
LiMn2O4 (LMO) powders were prepared by modified chemical bath deposition method. The effect of reaction time on the structure, morphology and optical properties of LMO nanostructures were investigated. The reaction time was varied from 1 - 120 min. The X-ray diffraction (XRD) patterns of the powders ...
Read More
LiMn2O4 (LMO) powders were prepared by modified chemical bath deposition method. The effect of reaction time on the structure, morphology and optical properties of LMO nanostructures were investigated. The reaction time was varied from 1 - 120 min. The X-ray diffraction (XRD) patterns of the powders correspond to the various planes of a cubic spinel LMO phase. It was observed that the secondary phases decreases with an increase in reaction time. The diffraction peaks increase in intensity with an increase in reaction time up to 10 min. The estimated average grain sizes calculated using the XRD spectra were found to be in the order of 60 ± 1 nm. The scanning electron microscope (SEM) image suggested that the reaction time influences the morphology of the prepared powders. The irregular nanoparticle increased in size with an increase in reaction time. The UV-Vis spectra showed a red shift with an increase in reaction time up to 10 min.
D. Saikia; P. Phukan; M. R. Das
Abstract
Solar cells with the structure ITO-Cu-CdS/PbS-Ag were fabricated by heat-induced Chemical Bath Deposition (CBD) technique. Cu-doped CdS/PVA nanocomposite thin film of thickness 260 nm was used as the window layer. The PbS absorber layer of different thickness (528.3 -1250.8 nm) for different molar concentration ...
Read More
Solar cells with the structure ITO-Cu-CdS/PbS-Ag were fabricated by heat-induced Chemical Bath Deposition (CBD) technique. Cu-doped CdS/PVA nanocomposite thin film of thickness 260 nm was used as the window layer. The PbS absorber layer of different thickness (528.3 -1250.8 nm) for different molar concentration of lead nitrate (0.05, 0.1, 0.15, 0.2 and 0.3 M) was then grown on ITO/CdS to fabricate the junction. The effect of molar concentrations on the optical and structural properties of the corresponding PbS films and solar cells were investigated. The optical bandgap of the PbS films was found to decrease with the increase of the molar concentration. The photovoltaic parameters such as short circuit current, open circuit voltage, fill factor and efficiency of the CdS/PbS solar cells were evaluated from the J-V characteristics under one sun illumination intensity (100mW/cm 2 ). The changing molar concentration enhanced the performances of the cells and a highest efficiency (1.38%) obtained at 0.3M molar concentration.
Somdatta Paul; Avishek Das; Mainak Palit; Satyaban Bhunia; Anupam Karmakar; Sanatan Chattopadhyay
Abstract
In this work, a comparative performance analysis of ZnO nanowires grown by following single- and double-step techniques on (100) p-Si substrate has been conducted. High-quality ZnO nanowires with c-axis orientation and perfect crystalline structures with appropriate chemical stoichiometry have been obtained ...
Read More
In this work, a comparative performance analysis of ZnO nanowires grown by following single- and double-step techniques on (100) p-Si substrate has been conducted. High-quality ZnO nanowires with c-axis orientation and perfect crystalline structures with appropriate chemical stoichiometry have been obtained from both the approaches. The areal density of the nanowires grown from double step approach is almost twice the nanowires grown by employing the single step approach. Histogram analysis shows that the diameter and height of majority of the single-step grown nanowires are ~370nm and ~2.45µm, and for the double step grown nanowires these are ~210 nm and ~2.16 µm, respectively. The bandgap values of the single-step and double-step grown nanowires are measured to 3.19eV and 3.26eV, respectively. The current-voltage characteristics of p-Si/n-ZnO diodes indicate that the forward current is contributed by both the electrons and holes and the relevant cut-in voltages are measured to be 0.5V and 2.5V, respectively.
Lehlohonolo F. Koao; Birhanu F. Dejene; Hendrik C. Swart; Setumo V. Motloung; Tshwafo E. Motaung; Shanganyane P. Hlangothi
Abstract
Tb3 + doped ZnO nanoparticles were synthesized using the chemical bath deposition (CBD) method at 80 ºC. All the samples were annealed at 700 ºC to remove the hydroxyl groups confirmed by the thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA). The thermal analysis, ...
Read More
Tb3 + doped ZnO nanoparticles were synthesized using the chemical bath deposition (CBD) method at 80 ºC. All the samples were annealed at 700 ºC to remove the hydroxyl groups confirmed by the thermogravimetric analysis (TGA) and differential thermogravimetric analysis (DTGA). The thermal analysis, structure, morphology and optical properties were characterized. The TGA and DTGA showed that the final yield decreases with an increase in the amount of molar concentration of Tb3 + ions. The X-ray diffraction (XRD) spectra of the ZnO: Tb3 + nanoparticles correspond to the various planes of hexagonal ZnO phase for the lower and higher Tb concentration samples. The estimated average grain sizes calculated using the XRD spectra were found to be in the order of 44 ±2 nm. The grain size was found to increase with an increase in the amount of Tb3+ ions. Scanning electron microscopy (SEM) micrographs showed nanoparticles are obtained for undoped ZnO and emergence of pyramids shape for higher molar concentration of Tb3 + ions. The reflectance spectra depict a red shift with an increase in Tb3 + molar concentration. Photoluminescence (PL) results showed that the luminescence intensity increased with an increase in the amount of Tb3 + ions.
B. Kavitha;M. Dhanam
Abstract
Near-stoichiometric and stoichiometric CBD CIAS thin films have been prepared onto well-cleaned substrates. EDAX spectra of the prepared thin films enabled to determine the film composition, stoichiometry nature, type of conductivity, lattice constants, volume of the unit cell and density of CIAS thin ...
Read More
Near-stoichiometric and stoichiometric CBD CIAS thin films have been prepared onto well-cleaned substrates. EDAX spectra of the prepared thin films enabled to determine the film composition, stoichiometry nature, type of conductivity, lattice constants, volume of the unit cell and density of CIAS thin films. The estimated compositional, structural and electrical parameters are presented and discussed in this paper in detail.
)