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Your search keyword '"O'Brien, D.F."' showing total 27 results
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27 results on '"O'Brien, D.F."'

6. Highly efficient phosphorescent emission from organic electroluminescent devices

Author

Baldo, M.A., O'Brien, D.F., You, Y., Shoustikov, A., Sibley, S., Thompson, M.E., and Forrest, S.R.

Subjects
Phosphorescence -- Research, Electroluminescence -- Research, Dyes and dyeing -- Research, Environmental issues, Science and technology, Zoology and wildlife conservation
Abstract

A fluorescent dye can improve the efficiency of electroluminescent organic light-emitting devices. High efficiency energy transfer from singlet and triplet states is reported in a material doped with phosphorescent dye 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine platinum (II) (PtOEP). Saturated red emission was generated with peak external and internal quantum efficiencies of 4% and 23%.

Published
1998

7. Alternating and direct current characterization and photoinduced absorption studies of modified conjugated polymer thin films

Author

Lipson, S.M.; Cadby, A.J., Bradley, D.D.C., Lane, P.A., Coleman, J.N., Drury, A., O'Brien, D.F., and Blau, W.J.

Subjects
Absorption -- Research, Dielectric films -- Research, Dielectric films -- Electric properties, Thin films -- Research, Thin films -- Electric properties, Polymers -- Research, Polymers -- Electric properties, Physics
Abstract

The electrical properties of the treated polymer films relative to conventional polymer films is studied. Photoinduced absorption measurements show a clear reduction in the formation of polarons in the treated films of PmPV, the result of which, coupled with the film thickness, absorption, photoluminescence spectral and efficiency measurements, supports the argument presented for an increased interchain separation in the treated films.

Published
2004

20. Asymmetric synthesis of unusual amino acids for peptide molecular design and molecular recognition studies.

Author

O'Brien, D.F., Glass, R. S., Miller, W. B., Forster, L.S., Li, Guigen., O'Brien, D.F., Glass, R. S., Miller, W. B., Forster, L.S., and Li, Guigen.

Abstract

Asymmetric synthetic organic chemistry of amino acids is of fundamental importance for the study of peptide and protein molecular design and molecular recognition. The designed unusual amino acids can provide unique conformational and topographical properties that are crucial for molecular recognition processes between peptide ligands and specific receptors, receptor subtypes, and the related signal transduction processes. It is necessary to design and synthesize optically pure unusual amino acids to meet different stereochemical requirements for different receptors and the various active sites on receptors. The Evans-type auxiliary has played an important role in the asymmetric synthesis of optically pure amino acids in the past decade. However, a lot of theoretical and practical research aspects in this field which are related to sensitive chiral enolates, new methodologies and new synthetic procedures need to be investigated. This thesis will present some new tactics for peptide molecular design, for asymmetric synthesis of β-branched α-amino acids and for the related mechanistic organic chemistry which include: a one-pot tandem Michael-like addition/electrophilic bromination reaction and its application to the total asymmetric synthesis of four individual four individual isomers of 2', β-di-methyl tyrosine; an efficient mono- and di-demethylation procedure for aryl-methyl ethers of unusual amino acids; 1,2-asymmetric cis electrophilic induction in allylic-strained boron enolates and its potential application for the asymmetric synthesis of unusual amino acids; a new strategy for the total synthesis of the four individual isomers of β-methylphenylalanine by using 4-phenyl-oxazolidinone as a new chiral resolution reagent and simultaneously as a chiral auxiliary which can provide complete stereoselectivities; a concise method to separate racemic Boc-amino acids, including Boc-unusual amino acids, and a new chiral resolution reagent for HPLC and NMR analysis; a mech

Published
1995

24. Improved energy transfer in electrophosphorescent devices.

Author

O'Brien, D.F., Baldo, M.A., Thompson, M.E., and Forrest, S.R.

Subjects
*QUANTUM electrodynamics, *PHOSPHORESCENCE, *PLATINUM, *BIPHENYL compounds
Abstract

Reports that external quantum efficiencies of up to (5.6+/-0.1)% at low brightness and (2.2+/-0.1)% at 100 cd/m[sup 2] were obtained from a red electrophosphorescent device containing the dye 2,3,7,8,12,13,17,19-octaethyl-21H23H-phorpine platinum(II) (PtOEP) doped in a 4,4',N,N'-dicarbazole-biphenyl host. Photoluminescent efficient of PtOEP; Efficiency loses due to nonradiative recombination.

Published
1999
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26. Rapid Chemical Vapor Deposition of Yba2cu3ox Coatings

Author

Lackey, W.J., primary, Carter, W.B., additional, Hill, D.N., additional, Barefield, E.K., additional, Hanigofsky, J.A., additional, Shapiro, M.J., additional, Moss III, T.S., additional, Green, A.J., additional, O'Brien, D.F., additional, Jake, R.A., additional, and Efferson, K.R., additional

Published
1989
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