Non-amine-based furan-containing oligoaryls as efficient hole transporting materials

A new class of highly stable furan-based hole transporting oligomeric materials, synthesized from the corresponding propargylic dithioacetals, serve as efficient hole transporting materials in electroluminescent devices. The performance of the devices using these furan materials is comparable with or somewhat better than those employing the conventional triarylamines (e.g. alpha-NPD).     

Restricted T-Universal Functions

We prove the existence of a function which is holomorphic exactly in the unit disk and has universal translates with respect to a prescribed closed set E∂ and satisfies C^∞(∂ \E). If Q is a subsequence of ₀ with upper density d(Q)=1 then the function can be constructed such that in addition

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On the regioselectivity of the beckmann rearrangement of cyclobutanones with o-mesitylene-sulfonylhydroxylamine : A convenient synthesis of substituted octahydrocyclopenta[b]pykroles

Cyclobutanones were smoothly transformed into γ-lactams by Tamura reagent. The stereoelectronic effects on the modified Beckmann rearrangenent were discussed. The extension to the synthesis of substituted octahydrocyclopenta[b]pyrroles was described.     

Synthesis, light-harvesting and energy-transfer properties of regioregular silylene-spaced alternating [(donor-SiMe2-)(n=1-3)-(acceptor-SiMe2)] copolymers

A series of silylene-spaced alternating [(donor-SiMe2)(n=1-3)-(acceptor-SiMe2)] copolymers 4-6 was synthesized by rhodium-catalyzed hydrosilylation of bisalkynes with bissilyl hydrides. Monomeric reference compounds 7-10 with similar chromophore components were prepared for comparison. The ratio of donor to acceptor groups is well-controlled by the precise regiochemistry and nature of the repeat units. The silylene moieties serve as insulating spacers between chromophores. The polymers exhibit light-harvesting abilities, for which the intensity of the emission enhanced with larger donor-to-acceptor ratios. No emission originating from the donors was observed in fluorescence spectra, illustrating that intrachain energy transfer is highly efficient along the polymer chain.     

Function space approach to a class of stochastic optimal control problems

The solution of the linear time-dependent stochastic optimal control problem with a quadratic performance index is well known. This paper presents a method of using this known solution to solve a class of problems which have the same system equations but with a class of non-quadratic performance indices.This work was partially supported by the Jet Propulsion Laboratory, California Institute of Technology, NASA Contract No. NAS 7-100.     

Electronic-structure dependence of the electron-phonon interaction in Ag

The linewidths of sp- and d-band derived electronic quantum-well states in thin films of Ag on Fe(100) are measured as a function of temperature to yield the electron-phonon coupling parameters. The results vary by a factor of up to 35 among the different states. The origin of these huge differences is traced to the decay path selection for the various initial states of the holes created by the photoemission process. The electron-phonon coupling parameter for the top d-band quantum-well state, 0.015+/-0.006, is the smallest ever reported.     

First examples of organophosphorus-containing materials for light-emitting diodes

Exploiting the reactivity of the P-atom of phosphole-based oligomers, we have achieved access to the first organophosphorus-containing organic light-emitting diode (OLED) materials. The versatility of these P-materials is demonstrated with the synthesis of a corresponding gold complex that has also been used as an OLED material. Optimization of the OLED devices by doping the phosphole layer with a red fluorescent dye is described.     

d-band quantum well states

Observations of d-band quantum well states are made for atomically uniform Ag films on Fe(100) using angle-resolved photoemission. For increasing film thicknesses, quantum well peaks within the small 4d bandwidth multiply rapidly and merge into a bulklike spectrum at approximately 25 monolayers. An analysis of the peak positions yields a highly accurate bulk band structure of Ag. A very narrow d-band peak width (13 meV) is observed at the band top.