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Facile synthesis, structure analysis and optical performance of manganese oxide-doped PVA nanocomposite for optoelectronic and optical cut-off laser devices
摘要： In the present work, successful manganese oxide (Mn2O3) nanoparticles (NPs) were synthesized by a combustion technique, while the casting process was employed for the manufacturing of polymer nanocomposites with various weights of Mn2O3 based on Poly(Vinyl Alcohol), PVA. Multiple methods such as X-ray diffraction (XRD), HR-TEM, EDAX, EDS, SEM, FT-IR, DTA analysis, optical spectroscopy from UV to IR regions, and optical reduction (CUT-OFF) setup were used to characterize the structural, elemental chemical analysis, morphological, optical properties, and cut-off laser characteristic of nanocomposite samples. Mn2O3 nanoparticles have a crystallite size of 22.08 nm as calculated using the Debye–Scherer formula from XRD, while the HR-TEM shows a spherical particle of size 30–38 nm range. EDAX spectra and EDS mapping were used to detect the elemental particles of the nanocomposite. The external morphology of the films by SEM images shows an increase in the agglomeration size of the cluster with the percentage of Mn2O3 nanoparticles in PVA. FT-IR spectra show excellent incorporation between the matrix of polymer and the Mn2O3 via the hydroxyl group. Moreover, with increasing the doping rate of nanoparticles, the thermal stability of PVA increased. A significant change of optical transmittance, absorption edge, Urbach energy, and transition bandgap have been observed due to the influence of Mn2O3. The comparison between the bandgap values that have been estimated from Tauc’s relation and thus resulting from optical dielectric loss indicates a direct allowed transition of electrons in the nanocomposites. The light is entirely UV–Vis absorbed by PVA with a high percentage of Mn2O3 nanoparticles. Moreover, the efficiency of the films to decrease the power of two laser beams (635 nm and 533 nm) has been observed. The flexible films of PVA with an elevated rate of Mn2O3 are considered a successful option for low-cost technologies of optical limiting.
关键词： Casting process,Combustion technique,PVA nanocomposite,Optoelectronic,Manganese oxide,Optical cut-off laser devices
更新于2025-09-19 17:13:59
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Microscopic Observation of Chalking in TiO<sub>2</sub> Particles Doped Photocatalytic Polymer Sheets
摘要： When TiO2 particle doped PVDF sheets are irradiated with UV-light, the sheets become cloudy, because local photocatalytic decomposition of PVDF leads to an increase in the surface roughness on a sub-micrometer scale. This is called “chalking”. Chalking results in decreased photocatalytic activity of the sheet. In this study, we investigated the chalking process of TiO2 doped PVDF sheets using SEM/EDX and AFM. In the first stage of chalking, minute cavities appear everywhere in the PVDF sheet surface. With UV-light irradiation, it is found that the density of minute cavities increases until they are connected laterally and then grow into minute cracks. When the decomposition of the PVDF progresses, TiO2 particle aggregates, which show cracks, are exposed on the surface. These results suggest that tensile stress builds up because of the PVDF decomposition.
关键词： AFM,Chalking,Polymer Sheet,Photocatalysis,Solvent Casting Process
更新于2025-09-09 09:28:46