PHOTOCONDUCTIVITY OF SOME POLYNUCLEAR AROMATIC HYDROCARBONS

1958 ◽  
Vol 36 (4) ◽  
pp. 607-614 ◽  
Author(s):  
J. Kommandeur ◽  
G. J. Korinek ◽  
W. G. Schneider
Keyword(s):  
Aromatic Hydrocarbons ◽  
Voltage Dependence ◽  
Singlet State ◽  
Spectral Response ◽  
Energy Levels ◽  
High Sensitivity ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Weak Absorption ◽  
Long Wavelength ◽  
Response Voltage

The spectral response, voltage dependence, and intensity dependence of the surface photocurrent in naphthalene, terphenyl, pyrene, stilbene, and azulene have been measured. Pyrene and naphthalene have a high sensitivity for photoconduction at the long-wavelength edge of the optical absorption spectrum. In the spectral response of pyrene three peaks appear at 4475 Å, 4275 Å, and 4100 Å. It is suggested that these peaks are due to weak optical absorptions to energy levels which are highly efficient in promoting conduction. It is possible that a similar effect occurs in naphthalene, where maximum photoconductivity coincides with a weak absorption reported by McClure and Schnepp. Azulene only shows photoconductivity at wavelengths corresponding to absorption to the second singlet state.

Zusammenhang zwischen Schweratominduzierter Fluoreszenzlöschung und Termschema von mehrkernigen aromatischen Kohlenwasserstoffen / Correlation between Heavy-atom induced Fluorescence Quenching and Energy Levels of Polynuclear Aromatic Hydrocarbons

1973 ◽  
Vol 28 (10) ◽  
pp. 1743-1744
Author(s):  
H. Dreeskamp ◽  
M. Zander
Keyword(s):  
Aromatic Hydrocarbons ◽  
Energy Gap ◽  
Energy Levels ◽  
Heavy Atom ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Intersystem Crossing ◽  
Triplet States ◽  
Excited Triplet ◽  
Wide Energy ◽  
Excited Triplet States

The observation that the fluorescence of certain polynuclear aromatic hydrocarbons (perylene, 1.2 ;5.6-dibenzoperylene, 9.10-diphenylanthracene and rubrene) is quenched by alkyl iodides only slightly is explained on the basis of the energy levels of these hydrocarbons. In these systems an effective radiationless desactivation of the fluorescing state S1 by intersystem crossing into the triplet manifold is prevented by a wide energy gap between S1 and the lowest triplet state, and the absence of excited triplet states below s,.

Analysis of the Bias Dependent Spectral Response of a-SiC:H p-i-n Photodiode

2002 ◽  
Vol 715 ◽  
Author(s):  
P. Louro ◽  
A. Fantoni ◽  
Yu. Vygranenko ◽  
M. Fernandes ◽  
M. Vieira
Keyword(s):  
Bias Voltage ◽  
Voltage Dependence ◽  
Spectral Response ◽  
Surface Recombination ◽  
Electrical Field ◽  
Field Reversal ◽  
Current Voltage ◽  
Voltage Dependent ◽  
And Inversion ◽  
Device Operation

AbstractThe bias voltage dependent spectral response (with and without steady state bias light) and the current voltage dependence has been simulated and compared to experimentally obtained values. Results show that in the heterostructures the bias voltage influences differently the field and the diffusion part of the photocurrent. The interchange between primary and secondary photocurrent (i. e. between generator and load device operation) is explained by the interaction of the field and the diffusion components of the photocurrent. A field reversal that depends on the light bias conditions (wavelength and intensity) explains the photocurrent reversal. The field reversal leads to the collapse of the diode regime (primary photocurrent) launches surface recombination at the p-i and i-n interfaces which is responsible for a double-injection regime (secondary photocurrent). Considerations about conduction band offsets, electrical field profiles and inversion layers will be taken into account to explain the optical and voltage bias dependence of the spectral response.

Multi-alkylated Polynuclear Aromatic Hydrocarbons of Tobacco Smoke: Separation and Identification

1978 ◽  
Vol 9 (4) ◽  
Author(s):  
M. E. Snook ◽  
R. F. Severson ◽  
R. F. Arrendale ◽  
H. C. Higman ◽  
O. T. Chortyk
Keyword(s):  
Liquid Chromatography ◽  
Cigarette Smoke ◽  
Aromatic Hydrocarbons ◽  
Ultra Violet ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Gel Chromatography ◽  
Cigarette Smoke Condensate ◽  
Gas And Liquid Chromatography ◽  
Silicic Acid Chromatography ◽  
Derivatives Of

AbstractThe methyl, multi-methyl, and ethyl derivatives of the polynuclear aromatic hydrocarbons (PAH) of cigarette smoke condensate (CSC) were isolated from the neutrals by silicic acid chromatography, solvent partitioning and gel chromatography. The procedure yielded a relatively pure PAH isolate amenable to further identifications. The multi-alkylated PAH were concentrated in the early gel fractions with parent and higher ring PAH found in subsequent gel fractions. It was shown that CSC is very rich in alkylated PAH, and their successful identification required extensive use of gas and liquid chromatography and ultra-violet and GC - mass spectrometric techniques. High-pressure liquid chromatography (HPLC) separated individual isomers of the alkylated PAH in complex GC peaks. PAH from indene to pentamethylchrysene were found. This report concludes our identification studies on the PAH of CSC and complements our two previous reports in this journal. Collectively, our studies have identified approximately 1000 PAH of cigarette smoke condensate and have led to the development of methods for the routine quantitation of PAH in smalI quantities of cigarette smoke condensate.

Spectrophotometry Measurement of Polynuclear Aromatic Hydrocarbons in Hamilton Harbour Sediments

1991 ◽  
Vol 26 (1) ◽  
pp. 1-16 ◽  
Author(s):  
T.P. Murphy ◽  
H. Brouwer ◽  
M.E. Fox ◽  
E. Nagy
Keyword(s):  
Aromatic Hydrocarbons ◽  
Total Concentration ◽  
Coal Tar ◽  
Sediment Cores ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Near Surface ◽  
Spectrometry Analysis ◽  
Hamilton Harbour

Abstract Eighty-one sediment cores were collected to determine the extent of coal tar contamination in a toxic area of Hamilton Harbour. Over 800 samples were analyzed by a UV spectrophotometric technique that was standardized with gas chromatography/mass spectrometry analysis. The coal tar distribution was variable. The highest concentrations were near the Stelco outfalls and the Hamilton-Wentworth combined sewer outfalls. The total concentration of the 16 polynuclear aromatic hydrocarbons (PAHs) in 48,300 m3 of near-surface sediments exceeded 200 µg/g.

Charge transfer energies of the complexes of (dibenzoylmethanato)boron difluoride with indeno-pyridines and polynuclear aromatic hydrocarbons

2013 ◽  
Vol 108 ◽  
pp. 181-185 ◽  
Author(s):  
Tandrima Chaudhuri ◽  
Sneha Salampuria ◽  
Pradip Kumar Tapaswi ◽  
Chhanda Mukhopadhyay ◽  
Subrata Chattopadhyay ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Aromatic Hydrocarbons ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Boron Difluoride

Extraction of low molecular weight polynuclear aromatic hydrocarbons from ashes of coal-operated power plants

1987 ◽  
Vol 59 (17) ◽  
pp. 2066-2069 ◽  
Author(s):  
Filippo. Mangani ◽  
Achille. Cappiello ◽  
Giancarlo. Crescentini ◽  
Fabrizio. Bruner ◽  
Loretta. Bonfanti
Keyword(s):  
Molecular Weight ◽  
Aromatic Hydrocarbons ◽  
Power Plants ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Low Molecular Weight
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