PHOTOCONDUCTIVITY AND ABSORPTION AND FLUORESCENCE SPECTRA OF 9,10-DICHLOROANTHRACENE

1958 ◽  
Vol 36 (3) ◽  
pp. 507-512 ◽  
Author(s):  
E. Bock ◽  
J. Ferguson ◽  
W. G. Schneider
Keyword(s):  
Absorption Spectrum ◽  
Light Intensity ◽  
Fluorescence Spectra ◽  
Spectral Response ◽  
Incident Light ◽  
Chloroform Solution ◽  
Absorption And Fluorescence Spectra ◽  
Crystal Face ◽  
Response Voltage ◽  
Temperature Dependences

The spectral response, voltage, light intensity, and temperature dependences of the photocurrent generated in crystals of 9,10-dichloroanthracene have been studied as well as the absorption and fluorescence spectra. The magnitude of the measured photocurrent was 102–103 times larger than that observed in anthracene under similar conditions. The spectral response of the photocurrent in the surface cell arrangement was found to depend on the direction of the incident light relative to the electrodes. Above a certain value of the applied voltage the photocurrent was found to be ohmic. The photocurrent increased as the 0.7 or 0.8 power of the light intensity depending on whether the light was incident on the same side or opposite sides of the crystal face containing the electrodes. When the crystal was cooled the photocurrent passed through a maximum between 20° and 0 °C.The absorption edge of crystalline 9,10-dichloroanthracene as well as the absorption spectrum in chloroform solution were determined. When the crystals were cooled the fluorescence spectrum was observed to shift to longer wavelengths and the intensity increased between two and three times.

Molecular Vibrations in the Exciton Theory for Molecular Aggregates. II. Dimeric Systems

1961 ◽  
Vol 14 (3) ◽  
pp. 344 ◽  
Author(s):  
EG McRae
Keyword(s):  
Absorption Spectrum ◽  
Perturbation Theory ◽  
Fluorescence Spectra ◽  
Numerical Calculations ◽  
Molecular Vibrations ◽  
Molecular Aggregates ◽  
Absorption And Fluorescence Spectra ◽  
Band Structures ◽  
Electronic Band ◽  
Electronic Band Structures

The theory of Part I of this series (McRae 1961) is developed in detail for dimeric systems. The simplest possible theory of the exciton states for a system of two non-rigid molecules is obtained through the use of perturbation theory. The theory makes possible the prediction of electronic band structures in absorption and fluorescence spectra as functions of the theoretical Davydov splitting for two rigid molecules. Numerical calculations are made for a dimer of a typical dye, and the results are compared with the observed absorption spectrum of the 1,1'-diethyl-2,2'-pyridocyanine iodide dimer.

Improved Concept for Nipiin and PIIIN Color Sensitive Two-Terminal Devices with High Linearity

1997 ◽  
Vol 467 ◽  
Author(s):  
D. Knipp ◽  
H. Stiebig ◽  
J. Fölsch ◽  
R. Carius ◽  
H. Wagner
Keyword(s):  
Light Intensity ◽  
Dynamic Range ◽  
Layer Structure ◽  
Spectral Response ◽  
Incident Light ◽  
High Dynamic Range ◽  
Optical Signal ◽  
Optimized Design ◽  
Defect States ◽  
Response Curves

ABSTRACTThe detection of the fundamental components of the visible light (blue, green, red) is achieved with two terminal photo diodes based on amorphous silicon. By changing the bias voltage the preferential carrier collection region is shifted which leads to a color sensitivity. In order to obtain a high dynamic range, independent voltage controlled spectral response curves as well as a linear response of the photocurrent on the incident light intensity the μτ-product and the bandgap in the device have to be specially designed to deconvolute the optical signal and generate an RGB-signal. Since the light intensity can strongly influence the spectral sensitivity by recharging of defect states, an optimized design of the multi-layer structure is necessary. Therefore, an improved concept for the design of nipiin- and piiin-detectors is presented which results in a good suppression of these non-linearities. Our concept is based on a decreasing bandgap profile from the front to the back contact and an increasing μτ-product of the individual i-layers in direction of the p-layer.

Electronic Absorption and Fluorescence Spectra of Matrix-Isolated CoCl2 Molecules

1970 ◽  
Vol 24 (1) ◽  
pp. 53-59 ◽  
Author(s):  
J. R. Clifton ◽  
D. M. Gruen
Keyword(s):  
Absorption Spectrum ◽  
Liquid Helium ◽  
Electronic Absorption ◽  
Fluorescence Spectra ◽  
Axial Ligand ◽  
Ligand Field ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Absorption And Fluorescence Spectra ◽  
Argon Matrix

The absorption spectrum of CoCl2 molecules isolated in a nitrogen matrix and the fluorescence spectrum of CoCl2 molecules isolated in an argon matrix have been measured at liquid helium temperatures in the range 4000–50 000 cm−1. The absorption and fluorescence spectra in the 4000–25 000 cm−1 region were not mutually observable in the same host. Interpretations of the spectra are given, based on axial ligand field calculations for a 3d7 configuration including spin-orbit coupling interactions.

Electronic Spectroscopy of Mixed Cyclophanes: [2.2](9,10)Anthraceno(1,4)naphthalenophane

1989 ◽  
Vol 42 (12) ◽  
pp. 2201 ◽  
Author(s):  
J Ferguson ◽  
RJ Robbins ◽  
GJ Wilson
Keyword(s):  
Absorption Spectrum ◽  
Single Crystal ◽  
Fluorescence Spectrum ◽  
Absorption Spectra ◽  
Fluorescence Polarization ◽  
Fluorescence Spectra ◽  
Electronic Spectroscopy ◽  
Absorption And Fluorescence Spectra ◽  
Absorption Bands ◽  
Absorption Intensity

The absorption and fluorescence spectra of [2.21(9,10) anthraceno (1,4) naphthalenophane are reported. The anisotropy of the absorption bands was measured by two methods, ( i ) from fluorescence polarization ratios in a rigid glass and (ii) from single crystal absorption spectra at 23 K. The two states arising from the 1La states of the two chromophores were identified together with two states arising from other chromophore 1B2u states. Two states arising from the 1La states of the two chromophores were also identified. Whereas a coupled chromophore model accounts reasonably well for the latter two states, the energies and intensities of the bands arising from 1La chromophore states cannot be reconciled with this approach. Long axis polarized absorption intensity lying under the 1La, bands appears to be vibronically induced and not due to the 1Lb states. The absorption spectrum, fluorescence spectrum and fluorescence polarization ratios of a stable dimer were also observed. Its structure is similar to that of the stable dimer of anthracene in which the molecular long axes are parallel but the short axes make an angle of about 70� with each other.

EFFECT OF SOLVENT ON NONLINEAR REFRACTIVE INDEX OF 2-(2′-HYDROXYPHENYL) BENZOXAZOLE

2003 ◽  
Vol 12 (03) ◽  
pp. 385-391
Author(s):  
GUILAN ZHANG ◽  
FEIBING XIONG ◽  
BAO ZHANG ◽  
GUOQING TANG ◽  
WENJU CHEN ◽  
...  
Keyword(s):  
Refractive Index ◽  
Excited State ◽  
Proton Transfer ◽  
Dimethyl Sulfoxide ◽  
Nonlinear Refractive Index ◽  
Fluorescence Spectra ◽  
Incident Light ◽  
Intramolecular Proton Transfer ◽  
Absorption And Fluorescence Spectra ◽  
Effect Of Solvent

Nonlinear refractive indexes n2 of 2-(2′-hydroxyphenyl) benzoxazole (HBO) in three species of solvent (cyclohexane, ethanol and dimethyl sulfoxide) have been determined by using the Z-scan technique. The experimental results show that the n2 of HBO is strongly dependent on the polarity of the solvent. Through the study on the absorption and fluorescence spectra of HBO in different solvents, we regard that the principal origin of the nonlinear refractive index of HBO is not the thermal effect because of absorption of incident light but the excited state intramolecular proton transfer of HBO under the incident light.

Effective Dielectric Function of Porous Silicon: the Transverse Component

1994 ◽  
Vol 358 ◽  
Author(s):  
G. Gumbs
Keyword(s):  
Absorption Spectrum ◽  
Absorption Coefficient ◽  
Electron Density ◽  
Quantum Wires ◽  
Interband Transition ◽  
Incident Light ◽  
Transverse Component ◽  
Effect Of Temperature ◽  
High Electron ◽  
Confining Potential

ABSTRACTA self-consistent many-body theory is developed to study the effect of temperature and electron density on the interband absorption coefficient and the frequency-dependent refractive index for an array of isolated quantum wires. The peaks in the absorption coefficient correspond to interband transitions resulting in the resonant absorption of light. The oscillations in the derivative spectrum are due to the quantization of the energy levels related to the in-plane confining potential for such reduced dimensional systems. There are appreciable changes in the absorption spectrum when the electron density or temperature is increased. One interband transition peak is suppressed in the high electron density limit and the thermal depopulation effect on the electron subbands can be easily seen when the temperature is high. We also find that the exciton coupling weakens the shoulder features in the absorption spectrum. This study is relevant to optical characterization of the confining potential and the areal density of electrons using photoreflectance. By using incident light with tunable frequencies in the interband excitation regime, contactless photoreflectance measurements may be carried out and the data compared with our calculations. By fitting the numerical results to the peak positions of the photoreflectance spectrum, the number of electrons in each wire may be extracted.

scholarly journals All organic multiferroic magnetoelectric complexes with strong interfacial spin-dipole interaction

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Yuying Yang ◽  
Zhiyan Chen ◽  
Xiangqian Lu ◽  
Xiaotao Hao ◽  
Wei Qin
Keyword(s):  
Magnetic Field ◽  
Light Intensity ◽  
Room Temperature ◽  
Incident Light ◽  
Dipole Interaction ◽  
Interfacial Interaction ◽  
Magnetoelectric Coupling ◽  
Incident Light Intensity ◽  
Organic Ferromagnets ◽  
Magnetoelectric Coefficient

AbstractThe organic magnetoelectric complexes are beneficial for the development on flexible magnetoelectric devices in the future. In this work, we fabricated all organic multiferroic ferromagnetic/ferroelectric complexes to study magnetoelectric coupling at room temperature. Under the stimulus of external magnetic field, the localization of charge inside organic ferromagnets will be enhanced to affect spin–dipole interaction at organic multiferroic interfaces, where overall ferroelectric polarization is tuned to present an organic magnetoelectric coupling. Moreover, the magnetoelectric coupling of the organic ferromagnetic/ferroelectric complex is tightly dependent on incident light intensity. Decreasing light intensity, the dominated interfacial interaction will switch from spin–dipole to dipole–dipole interaction, which leads to the magnetoelectric coefficient changing from positive to negative in organic multiferroic magnetoelectric complexes.

A renewable photocatalytic system with dramatic photocatalytic activity for H2 evolution and constant light energy utilization: Eosin Y sensitized ZnWO4 nanoplates loaded with CuO nanoparticles

2021 ◽  
Author(s):  
Xiaoluo Bao ◽  
Xiaokun Wang ◽  
Xiangqing Li ◽  
Lixia Qin ◽  
Taiyang Zhang ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Light Intensity ◽  
Incident Light ◽  
Cuo Nanoparticles ◽  
Energy Utilization ◽  
Limited Attention ◽  
Eosin Y ◽  
H2 Evolution ◽  
Incident Light Intensity ◽  
Photocatalytic System

It is necessary for the commercialization of sunlight-driven H2 evolution to develop an efficient photocatalytic system whose energy utilization is independent on incident light intensity. Unfortunately, limited attention has been...

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