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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
Search results
Showing 141 to 150 of 686 (0.013 seconds)| 141 |
Radiochemical studies of neutron induced fission in heavy nuclidesBirgul, O. January 1968 (has links)
No description available.
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| 142 |
Some studies of the quenching of O('D) atoms produced in the flash photolysis of ozoneLangley, K. F. January 1970 (has links)
No description available.
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| 143 |
Some studies on the chemiluminescent reactions of photochemically generated speciesThompson, M. January 1971 (has links)
No description available.
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| 144 |
The Study of Magnesium and the Alkaline Earth Metals by Absorption Flame PhotometryMagill, W. A. January 1973 (has links)
No description available.
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| 145 |
A laser pulse technique for the investigation of chemical relaxation processesJamison, R. S. January 1972 (has links)
No description available.
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| 146 |
Perturbation corrections to the frozen core approximation for the lithium sequenceMurphy, G. January 1978 (has links)
No description available.
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| 147 |
The dissociative photoionization of molecular hydrogenStrathdee, S. January 1979 (has links)
No description available.
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| 148 |
The photochemistry of dye and pigment systemsMcVie, J. January 1979 (has links)
No description available.
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| 149 |
Luminescence of Hydrocarbon polymers and Related model compoundsBouotead, I. January 1969 (has links)
No description available.
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| 150 |
Light-emitting diodes from polyfluorenes : characterisation and stability of performanceSeeley, Alexander J. A. B. January 2003 (has links)
This thesis deals with polymer light-emitting diodes (LEDs) containing materials from the polyfluorene family, and investigates their behaviour when employed in device structures. A study of poly(9,9'-dioctylfluorene-co-bis-N,N'-(4-butylphenyl)-bis-N,N'-phenyl-1,4-phenylenediamine) (PFB) by photothermal deflection spectroscopy (PDS) shows that thepolymer undergoes a doping reaction with poly(styrene sulphonic acid). This is important because the two materials are found in intimate contact in LED structures. The conditions for reaction are investigated, and it is proposed that the reacted states are directly responsible for the drive-induced degradation of LEDs containing these two materials. LEDs are studied which contain various combinations of poly(9,9'-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine) (TFB) and poly(9,9'-dioctylfluorene-co-benzothiadiazole) (F8BT), using pulsed electroluminescence. A strongly morphology-dependent spike-transient is observed in the electroluminescence at turn-on, and this is investigated by numerical modelling. Although not all features of the system can be well represented in the model, the spike transient is explicitly predicted without the need to impose any special conditions. The origin of this feature is elucidated by repeatedly running the model to a range of end-points and studying the time-evolution of space-charge distributions which result. Finally, F8BT devices are considered on their own, in order to study the evolution of device performance under low-intensity electrical excitation. A phenomenon is investigated in which the quantum efficiency is dramatically increased during the early stages of driving. Ionic motions are ruled out, and the observations are attributed to the trapping of charge in the vicinity of the anode, leading to enhanced hole injection. The reverse-bias behaviour of the effect, in which a further enhancement is seen, is also examined. The analogy is made with polymer LEDs in general which increase in performance following a period of reverse bias, and it is suggested that the causes may be related.
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