scholarly journals Ring fusion in tetrathienylethene cored perylene diimide tetramers affords acceptors with strong and broad absorption in the near-UV to visible region

2020 ◽  
Vol 8 (48) ◽  
pp. 17237-17244
Author(s):  
Qiao He ◽  
Flurin D. Eisner ◽  
Drew Pearce ◽  
Thomas Hodsden ◽  
Elham Rezasoltani ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Dft Calculations ◽  
Absorption Spectra ◽  
Organic Photovoltaics ◽  
Visible Region ◽  
Perylene Diimide ◽  
Optical Absorption Spectra ◽  
Broad Absorption ◽  
Ring Fusion

Two PDI tetramers with a central tetrathienylethene core were investigated as non-fullerene acceptors in organic photovoltaics and the dramatic differences in their optical absorption spectra were rationalised on the basis of DFT calculations.

scholarly journals A theoretical study on photo absorption in silicon decorated boron clusters (BnSi, n=7-10)

2021 ◽  
Vol 2070 (1) ◽  
pp. 012051
Author(s):  
Ankita Jaiswal ◽  
Shakti S Ray ◽  
Sridhar Sahu
Keyword(s):  
Optical Absorption ◽  
Oscillator Strength ◽  
Absorption Spectra ◽  
Density Functional ◽  
Visible Region ◽  
Basis Set ◽  
Functional Study ◽  
Strength Analysis ◽  
Optical Absorption Spectra ◽  
Boron Clusters

Abstract In this work, we have studied the optical absorption spectra of small boron clusters doped with single silicon atom (BnSi, n=7-10) and is reported employing CAM-B3LYP functional with 6-311+G(d) basis –set within the framework of time dependent density functional study (TD-DFT). We have computed excitation energy, oscillator strength, wavelength and the corresponding orbital transitions associated with a given oscillator strength. Analysis of optical absorption spectra of studied clusters shows that most of the absorption peaks are found in the ultraviolet-visible (UV-Vis) region (200 nm-700 nm). The major peaks are found to fall in UV region along with some weaker peaks at visible region. The most intense peak is recorded for B8Si cluster at 232 nm and oscillator strength of 0.084. This peak is associated with the orbital transition from H-4→L+1.

Quantum Confinement Effects in Calcium Sulfide: The Role of Indirect Transitions in the Red Shift of the Band Edge in Semiconductor Nanoparticles

2014 ◽  
Vol 1694 ◽  
Author(s):  
Daniel Rivera-Vázquez ◽  
Yohaselly Santiago-Rodríguez ◽  
Miguel A. González ◽  
Miguel E. Castro-Rosario
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Quantum Confinement ◽  
Visible Region ◽  
Calcium Sulfide ◽  
Optical Absorption Spectra ◽  
Confinement Effects ◽  
Absorption Bands ◽  
Long Wavelength ◽  
Quantum Confinement Effects

ABSTRACTCalcium sulfide (CaS) nanoparticles are cadmium free fluorescent nanostructures with potential applications in nanomedicine and photovoltaic cells. We report on the synthesis and optical properties of CaS nanoparticles prepared by the reaction of Ca(CH3CO2)2 and DMSO in a microwave. The absorption spectra of CaS prepared from this method consists of a well-defined peak in the UV and a long wavelength tail that extends above 700 nm. Emission bands centered at around 500 nm with a long wavelength tail that extends above 600 nm are observed upon excitation at 405 nm. STM measurements reveal the formation of CaS nanoparticles with an average diameter of (3.2 ± 0.7) nm. The direct and indirect band gaps are estimated to be (0.403 ± 0.003) eV and (4.135 ± 0.006) eV, respectively. Theoretical calculations on small CaS clusters are used to establish the physical properties of calcium sulfide nanoclusters, including the optical absorption spectra. Unique to CaS nanostructures is the absorption of light at wavelengths longer that in the bulk material instead of the blue shift associated with quantum confinement effects in semiconductors. Indeed, the strong absorption bands in the visible region of the spectra of the CaS nanostructures do not have a counterpart in the gas or solid phases. The optical absorption spectra are proposed to have a significant contribution from indirect transitions which are discussed in terms of the dispersion of the phonon frequency.

scholarly journals OPTICAL ABSORPTION SPECTRA OF TERNARY COMPLEX OF PRASEODYMIUM IN DIFFERENT ENVIRONMENT

2013 ◽  
Vol 22 ◽  
pp. 431-438
Author(s):  
ANUP KUMAR GUPTA ◽  
SHRI KISHAN UJJWAL
Keyword(s):  
Acetic Acid ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Ternary Complex ◽  
Visible Region ◽  
Experimental Result ◽  
Optical Absorption Spectra ◽  
Analytical Instrument ◽  
Good Agreement ◽  
Secondary Ligand

The optical absorption spectra of complex of Praseodymium in different solvents i.e water, Methanol, Ethanol & Acetic Acid have been recorded in visible region (360-620 nm for Pr3+ ) using amino acid as primary ligand and diol as secondary ligand. The value of energies & intensities of various transitions have been calculated using Judd-Ofelt relation is in good agreement with experimental result. The study of complex found it to be covalent in nature. The spectra in visible region have been recorded on model uv-2601 Rayleigh analytical instrument corp.

scholarly journals Fast optical absorption spectra calculations for periodic solid state systems

2020 ◽  
Vol 15 (1) ◽  
pp. 89-113
Author(s):  
Felix Henneke ◽  
Lin Lin ◽  
Christian Vorwerk ◽  
Claudia Draxl ◽  
Rupert Klein ◽  
...  
Keyword(s):  
Solid State ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Optical Absorption Spectra

NIR and Upconversion Luminescence Properties of Nd3+ Doped in Gd2O3-CaO-SiO2-B2O3 Glass System

2014 ◽  
Vol 548-549 ◽  
pp. 124-128 ◽  
Author(s):  
S. Insiripong ◽  
S. Kaewjeang ◽  
U. Maghanemi ◽  
H.J. Kim ◽  
N. Chanthima ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Concentration Quenching ◽  
Luminescence Spectra ◽  
Optical Absorption Spectra ◽  
Glass Matrices ◽  
Nir Luminescence

In this work, properties of Nd3+ in Gd2O3-CaO-SiO2-B2O3 glass systems with composition 25Gd2O3-10CaO-10SiO2-(55-x)B2O3-xNd2O3 where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol% were investigated. The optical absorption spectra show peaks at 4F3/2 (877 nm) , 4F5/2+2H9/2 (802 nm), 4F7/2+4S3/2 (743 nm), 4F9/2 (682 nm), 2H11/2 (627 nm), 2G7/2 +4G5/2 (582 nm), 4G7/2 +2K13/2 (527 nm), 4G11/2 (481 nm), 2P1/2 (427 nm) and 2L15/2 + 4D1/2 + 1I11/2+ 4D5/2+ 4D3/2 (355 nm) reflecting the Nd3+ ions in glass matrices. The densities were increased with increasing of Nd2O3 concentration. This indicates the increase of the molecular weight by the replacement of B2O3 with a heavier Nd2O3 oxide in the glass. The upconversion luminescence spectra show bands at 393 nm for all Nd2O3 concentration and the strongest intensity from 2.5 % mol of Nd2O3 was obtained. For NIR luminescence, the intensity of Nd3+ emission spectra increases with increasing concentrations of Nd3+ up to 1.5 mol% and beyond 1.5 mol% the concentration quenching is observed.

OPTICAL ABSORPTION SPECTRA OF ARSENIC AND PHOSPHORUS IN SILICON

1962 ◽  
Vol 40 (10) ◽  
pp. 1480-1489 ◽  
Author(s):  
J. W. Bichard ◽  
J. C. Giles
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Excited States ◽  
Ground State ◽  
Absorption Lines ◽  
Full Width ◽  
Optical Absorption Spectra ◽  
Phosphorus Impurity ◽  
Line Widths ◽  
Phosphorus In Silicon

The optical absorption spectra of arsenic and phosphorus donor impurities in silicon have been studied under conditions of improved resolution. Absorption lines due to transitions from the impurity ground state to the excited states 2p0, 2p±, 3p0, 3p±, 4p0, 4 p±, and 5p0, and 5p± have been observed at 4.2° K. The relative intensities of some of these absorption lines are compared with existing experimental and theoretical estimates. The contribution of instrumental broadening to the observed line widths is assessed and natural line widths are estimated. The estimates indicate values for the natural line widths which are much less than those previously reported. For phosphorus impurity, the natural line widths are estimated to be less than 0.08 × 10−3 electron volts full width at half-maximum. The possibility of concentration broadening is discussed in connection with the arsenic data.

Sign in / Sign up

Export Citation Format

Share Document