Excitonic Bands in the Optical Absorption Spectra of A3MX6 and A3M2X9 (A = MeNH3, Me2NH2, Me3NH, Me4N; M = Bi, Sb; X = Cl, Br, I)

1994 ◽  
Vol 49 (6) ◽  
pp. 849-851 ◽  
Author(s):  
G. C. Papavassiliou ◽  
I. B. Koutselas
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Spectral Region ◽  
Visible Spectral Region ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
Uv Visible ◽  
Low Dimensional

The title compounds (natural low-dimensional semiconductors) show strong excitonic optical absorption bands in the UV-visible spectral region, because of the dielectric confinement of excitons. as in the cases of other similar systems based on PbX2-4, SnX2-4. PtI - X - PtIV-X , Cdx,Sy-clusters etc

Preparation and Characterization of (C6H5CH2CH2NH3)4BiI7 · H2O, (C6H5CH2CH2NH3)3BiBr6 and (C6H5CH2CH2NH3)3BiCl6

1995 ◽  
Vol 50 (10) ◽  
pp. 1566-1569 ◽  
Author(s):  
G. C. Papavassiliou ◽  
I. B. Koutselas ◽  
A. Terzis ◽  
C. P. Raptopoulou
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Spectral Region ◽  
Visible Spectral Region ◽  
Optical Absorption Spectra ◽  
Uv Visible

The title compounds were prepared and characterized analytically, structurally, and spectroscopically. They contain isolated BiX6 (X = I. Br, Cl) anions. Their optical absorption spectra show excitonic bands in the UV-visible spectral region. These bands occur at higher energies than the corresponding bands of R3M2X9 (R = MemNH4-m; m = 1,2, 3, 4).

scholarly journals Excitonic Bands in the Optical Absorption Spectra of (Bu4N)CuBr2, (Et4N)2Cu2Br4, (Pr4N)2Cu4Br6, (Bu4N)2Cu2I4, (Me4N)Cu2I3, (Pr4N)4Ag4I8, (Me4N)Ag2I3, (Et4N)Ag2Br3, and Similar Compounds

1999 ◽  
Vol 54 (1) ◽  
pp. 109-112 ◽  
Author(s):  
G. C. Papavassilioua ◽  
G. A. Mousdis ◽  
A. Terzis ◽  
C. P. Raptopoulou
Keyword(s):  
Optical Absorption ◽  
Spectral Region ◽  
Quantum Confinement ◽  
Optical Absorption Spectra ◽  
Bulk Materials ◽  
Trivalent Metal ◽  
Absorption Bands ◽  
Bivalent Metal ◽  
Halide Complexes ◽  
Low Dimensional

The title compounds (natural low-dimensional semiconductor systems) exhibit strong excitonic optical absorption bands in the UV spectral region, because of the quantum confinement of excitons, as in the cases of bivalent-metal and trivalent-metal halide complexes. The excitonic bands are shifted to longer wavelengths, approaching those of the corresponding bulk materials, as the anion-size or the anion-dimensionality increases.

Optical Absorption of Doped and Undoped Bulk SiC

2000 ◽  
Vol 640 ◽  
Author(s):  
K. Miller ◽  
Q. Zhou ◽  
J. Chen ◽  
M. O. Manasreh ◽  
Z. C. Feng ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Optical Absorption ◽  
Band Gap ◽  
Absorption Spectra ◽  
Spectral Region ◽  
Sharp Peak ◽  
Band Edge ◽  
Optical Absorption Spectra ◽  
Bulk Silicon ◽  
Free Carriers

ABSTRACTOptical absorption spectra of undoped, n-type, and semi-insulating 6H and 4H bulk silicon carbide (SiC) were obtained in the spectral region of 200 – 3200 nm (6.20 – 0.3875 eV). Several features were observed in the absorption spectra collected for various samples. A sharp peak below the band gap was observed in 4H SiC. The intensity of this peak was observed to increase in samples that exhibit larger absorption due to free carriers, which leads us to conclude that the defect responsible for this peak is also the source of the free carriers in the materials. Additionally, a series of optical absorption peaks separated by approximately 21 meV were observed around 0.9185 eV (1350 nm). These peaks are zero phonon lines of intraband transitions in the VSi 3d shell. The optical absorption near the band edge was observed to be sample dependent. The variation of the band gap as a function of temperature is also observed to be sample dependent.

The role of dysprosium ions on the physical and optical properties of lithium-borosulfophosphate glasses

2017 ◽  
Vol 31 (13) ◽  
pp. 1750101 ◽  
Author(s):  
Ibrahim Bulus ◽  
S. A. Dalhatu ◽  
R. Hussin ◽  
W. N. Wan Shamsuri ◽  
Y. A. Yamusa
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Physical Parameters ◽  
Potential Candidate ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
X Ray ◽  
Nir Absorption ◽  
Optical Applications

Achieving outstanding physical and optical properties of borosulfophosphate glasses via controlled doping of rare earth ions is the key issue in the fabrication of new and highly-efficient glass material for diverse optical applications. Thus, the effect of replacing P2O5 by Dy2O3 on the physical and optical properties of Dy[Formula: see text]-doped lithium-borosulfophosphate glasses with chemical composition of 15Li2O–30B2O3–15SO3–[Formula: see text]P2O5–[Formula: see text]Dy2O3 (where 0.0 mol.% [Formula: see text] mol.%) has been investigated. The glass samples were synthesized from high-purity raw materials via convectional melt-quenching technique and characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectrometry (EDX), density and UV–vis–NIR absorption measurements. The amorphous nature of the prepared glass samples was confirmed by XRD patterns whereas the EDX spectrum depicts elemental traces of O, C, B, S, P and Dy. The physical parameters such as density, refractive index, molar volume, polaron radius and field strength were found to vary nonlinearly with increasing Dy2O3 concentration. UV–vis–NIR absorption spectra revealed seven absorption bands with most dominant peak at 1269 nm (6H[Formula: see text]F[Formula: see text]H[Formula: see text]). From the optical absorption spectra, the optical bandgap and Urbach’s energy have been determined and are related with the structural changes occurring in these glasses with increase in Dy2O3 content. Meanwhile, the bonding parameters ([Formula: see text]) evaluated from the optical absorption spectra were found to be ionic in nature. The superior features exhibited by the current glasses nominate them as potential candidate for nonlinear optical applications.

Notizen: Preparation, Structures and Optical Properties of [H3N(CH2)6NH3]BiX5 (X=I, Cl) and [H3N(CH2)6NH3]SbX5 (X=I, Br)

1998 ◽  
Vol 53 (8) ◽  
pp. 927-932 ◽  
Author(s):  
G. A. Mousdis ◽  
G. C. Papavassiliou ◽  
A. Terzis ◽  
C. P. Raptopoulou
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Crystal Structures ◽  
Absorption Spectra ◽  
Blue Shift ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
One Dimensional ◽  
Excitonic Absorption

Abstract The preparation, crystal structures and optical absorption spectra of [H3N(CH2)6NH3]BiX5 (X= I, Cl) and [H3N(CH2)6NH3]SbX5 (X =I, Br) are reported. The anions of the compounds consist of MX6-octahedra (M =Bi, Sb) sharing cisvertices in one-dimensional zig-zag chains. Because of their one-dimensional character, a blue shift of the excitonic absorption bands, in com parison to those of higher dim ensionality systems (MX3), is observed.

Investigation on Physical and Optical Properties of Vanadium Oxide in Soda Lime Borate Glasses

2014 ◽  
Vol 979 ◽  
pp. 135-138 ◽  
Author(s):  
Yotsakit Ruangtaweep ◽  
Jakrapong Kaewkhao
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Optical Absorption ◽  
Vanadium Oxide ◽  
Absorption Spectra ◽  
Soda Lime ◽  
Borate Glasses ◽  
Optical Absorption Spectra ◽  
Color Coordinate ◽  
Uv Visible

In this work, the physical and optical properties of soda-lime-borate glasses doped with V2O5 concentration of 0.0 to 2.5 in mol% have been investigated. The glass samples were prepared by the normal melt-quench technique. The results show that the density and refractive index decreased with additional 0.5 mol% content of V2O5. Then both results increased with increasing V2O5 content from 1.0-2.5 mol%. The optical absorption spectra of glass samples were measured by UV-visible spectrophotometer in the wavelength range 300-1100 nm and color coordinate in CIEL*a*b* system. The absorption peaks locate around 605 and 960 nm for all V2O5 concentration that are associated to V4+ ions and produce the brown color.

Optical Absorption Spectra of KBr:Pb2+ Crystals

1973 ◽  
Vol 51 (21) ◽  
pp. 2242-2248 ◽  
Author(s):  
Robert E. Chaney ◽  
P. W. M. Jacobs ◽  
Taiju Tsuboi
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Alkali Halide ◽  
Room Temperature ◽  
Nonlinear Least Squares ◽  
Energy Separation ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
Fundamental Properties ◽  
Alkali Halide Crystals

The fundamental properties of the absorption spectra of KBr:Pb2+ crystals have been studied at various temperatures from the liquid helium range to room temperature. The observed absorption bands are assigned to the so-called A, B, C, and D' bands by analogy with the absorption bands of other s2-configuration ions in alkali halide crystals. The B, C, and D′ bands overlap but have been resolved into their components by nonlinear least squares analysis. A discussion is given of the energy separation between the B and C bands in Sn2+-, Tl+-, and Pb2+-doped alkali halide crystals.

Effects of Ni2+ Ions on Soda Lime Silicate Glasses

2013 ◽  
Vol 770 ◽  
pp. 307-310 ◽  
Author(s):  
Wichian Siriprom ◽  
Kanyakorn Teanchai ◽  
Onanong Chamlek ◽  
Sirisit Sukphirom ◽  
Yotsakit Ruangtaweep ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Soda Lime ◽  
Silicate Glasses ◽  
Refractive Indices ◽  
Optical Absorption Spectra ◽  
Uv Visible ◽  
Glass Matrices

In this work, effects of Ni2+ ions on soda lime silicate glasses have been investigated. Glasses were prepared in formula (65-x)SiO2 : 25Na2O : 10CaO: xNiO (where x is 0.00, 0.02, 0.04, 0.06, 0.08 and 0.10 mol%). The densities of glasses not depend on Ni2+ concentration. The refractive indices decreased with increasing of NiO concentration. The optical absorption spectra were measured by uv-visible spectrophotometer and show peaks correspond with Ni2+ in glass matrices. Both of octahedral transitions and tetrahedral transition from Ni2+ ion were found around 450 and 625 nm respectively. The color of glasses were also measured in CIE L* a* b* system.

scholarly journals Microwave and Induction Heating-Assisted Biosynthesis of 12CaO 7Al2O3 Electride from Aloe Vera Leaf Extract

2021 ◽  
Vol 27 (1) ◽  
pp. 84-89
Author(s):  
Waramon LANGLAR ◽  
Areeya AEIMBHU ◽  
Pichet LIMSUWAN ◽  
Chesta RUTTANAPUN
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Induction Heating ◽  
Aloe Vera ◽  
Process Time ◽  
Heating Process ◽  
Microwave Assisted Synthesis ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
Precursor Powders

The white powders used as precursor powders for the synthesis of 12CaO×7Al2O3 electride (C12A7:e-) were prepared by biosynthesis method using Aloe vera extract and microwave assisted synthesis. The C12A7:e- crystals were synthesized by induction heating process under a reducing atmosphere at different times of 3, 4 and 5 min. The structure of C12A7:e- powders was characterized by X-ray diffraction. The XRD analysis revealed that pure C12A7:e- powders were obtained from white precursor powders with an induction heating process time of 5 min. To confirm that the white precursor powders were transformed into C12A7:e- after induction heating process for 3, 4 and 5 min, the optical absorption spectra of powders were investigated by an UV-Vis diffuse reflectance spectrometer in the wavelength range of 200 – 800 nm. The results show the optical absorption bands at 2.8 eV for the white precursor powders with induction heating time of 3, 4 and 5 min. This is due to the C12A7 was transformed into electride (C12A7:e-). Therefore, the results on the optical absorption spectra are in good agreement with the XRD results.

Effect of CoO Addition on the Optical and Physical Properties of Silicoborate Glasses

2016 ◽  
Vol 675-676 ◽  
pp. 318-321
Author(s):  
Wichian Siriprom ◽  
Kanyakorn Teanchai ◽  
Nattapon Srisittipokakun ◽  
Jakrapong Kaewkhao
Keyword(s):  
Refractive Index ◽  
Optical Absorption ◽  
Physical Properties ◽  
Absorption Spectra ◽  
Optical Absorption Spectra ◽  
Uv Visible ◽  
Glass Matrices

In this work, effects of CoO on silicoborate glasses have been investigated. Glasses were prepared in formula (53-x)B2O3:11SiO2:32SrO:1Bi2O3:1TiO2: xCoO (where x is 0.00, 0.01, 0.02, 0.03, 0.04 and 0.05 mol%). The results show that, the density and refractive index were increased with increasing of CoO concentration. The optical absorption spectra were measured by UV-Visible Spectrophotometer and show peaks correspond with Co2+ in glass matrices at a wavelength of around 511 584 and 649 nm for all glass samples.

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