Effect of proton uptake on the structure of energy levels in the band-gap of Sr-doped LaScO3: diffuse reflectance spectroscopy and coherent potential approximation calculations

2019 ◽  
Vol 21 (15) ◽  
pp. 7989-7995 ◽  
Author(s):  
Maxim I. Vlasov ◽  
Veronika M. Zainullina ◽  
Michael A. Korotin ◽  
Andrei S. Farlenkov ◽  
Maxim V. Ananyev

The obtained results explain features of LaScO3 optical properties and the effect of acceptor doping and H2 and H2O uptake on them.

2021 ◽  
Vol 21 (3) ◽  
pp. 537
Author(s):  
Siham Lhimr ◽  
Saidati Bouhlassa ◽  
Bouchaib Ammary

ZnO is one of the most studied semiconductor materials because of its interesting chemicals, and from a technological point of view, mainly as a consequence of their outstanding properties, such as wurtzite type, non-toxic nature, large band gap, low cost, and environment-friendly. In this work, the ZnO/C composite was synthesized by a simple and fast low-temperature method; the solid product was calcination temperature at 100 to 400 °C. The influence of variation in calcination temperature was studied using X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV-visible diffuse reflectance spectroscopy. The X-ray diffraction patterns indicated a high crystallinity and a nanocrystalline size of the ZnO/C composite hexagonal structure of wurtzite. The SEM image of the samples showed that the powder has a spherical structure of flakes aggregated in the common nucleus like a grid. The sphere consists of spindle and flower-like structures. The optical properties were determined by UV-vis diffuse reflectance spectroscopy, and it was found that the band gap energy of ZnO/C composite increase from 3.210 to 3.329 eV with an increase in calcination temperature from 100 to 400 °C. FTIR spectra and EDS analysis showed that the existence of carbon in the composite.


2006 ◽  
Vol 39 (18) ◽  
pp. 41-46
Author(s):  
Emilie Péry ◽  
Walter C.P.M. Blondel ◽  
Cédric Thomas ◽  
Jacques Didelon ◽  
François Guillemin

2019 ◽  
Vol 17 (1) ◽  
pp. 1198-1212 ◽  
Author(s):  
Teguh Endah Saraswati ◽  
Umam Hasan Setiawan ◽  
Mohammad Rifki Ihsan ◽  
Isnaeni Isnaeni ◽  
Yuliati Herbani

AbstractC60 fullerene exhibits unique optical properties that have high potential for wide photo-optical applications. To analyze the optical properties of C60, its excitation and emission properties were studied using UV-Vis absorption and photoluminescence (PL) spectroscopy, which were performed in various, non-polar organic solvents such as toluene, xylene, and trichloroethylene (TCE). The C60 solutions in toluene, xylene, and TCE displayed similar excitation bands at 625, 591, 570, 535, and 404 nm corresponding to Ag → T1u and Ag → T1g transitions. However, these bands differed from the solid C60 observed by UV-Vis diffuse reflectance spectroscopy. The two emission band energies of C 60 solution in toluene and xylene were nearly the same (1.78 and 1.69 eV), whereas the C60 solution in TCE was shifted to 1.72 and 1.65 eV. Because the polarity of TCE is higher than that of toluene and xylene, the PL spectrum of the C 60 solution in TCE was red-shifted. The PL spectroscopy had a better capability than UV-Vis absorbance spectroscopy to distinguish the different interactions between C60 and the organic solvents due to their different solvent polarities.


2015 ◽  
Author(s):  
Anne Koenig ◽  
Blandine Roig ◽  
Jimmy Le Digabel ◽  
Gwendal Josse ◽  
Jean-Marc Dinten

2019 ◽  
Author(s):  
Steven L. Jacques ◽  
Daniel Wangpraseurt ◽  
Michael Kühl

AbstractThe internal light field and thus light exposure of the photosymbiotic microalgae (Symbiodinium sp.) in corals is strongly modulated by the optical properties of coral tissue and skeleton. While there are numerous studies documenting the light microenvironment in corals, there are only few measurements of the inherent optical properties of corals in the literature, and this has hampered a more quantitative understanding of coral optics. Here we present a study of the optical properties of 26 live coral samples, representative of 11 coral species and spanning a variety of morphotypes. We employed well-established fiber-optic reflectance spectroscopy techniques from biomedical optics using two methods: (1) A source and a detection fiber separated by a variable distance measured the lateral spread of light in corals, dominated by the skeleton; (2) A fiber-optic field radiance probe measured the diffuse reflectance from the coral surface, dominated by the living coral tissue. Analysis based on diffusion theory and Monte Carlo simulation yielded estimates of the bulk scattering and absorption coefficients of the coral tissue and skeleton, in the 750-1030 nm wavelength range. Extrapolating into the spectral region of photosynthetically active radiation (PAR, 400-700 nm) allowed estimation of the optical depth of absorption by the main Symbiodinium photopigment chlorophyll a. Coral tissue scattering was on average ~1.9x stronger than the scattering of the skeleton, consistent with the model that corals trap photons by high scattering to enhance absorption by algal pigments, while the lower scattering of the skeleton allows spread of light to otherwise shaded coral tissue areas.


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