Search results for "phosphore"

Possible mechanism of energy storage in optically stimulable materials: doped alkali halides

1997

Radiation-induced effects in doped alkali halides, mainly in KBr:In, are studied by the luminescence technique. The activator luminescence during a 10 s under UV-light or electron irradiation and, after it, the pulsed photostimulated luminescence on a phosphorescence background were investigated. The obtained results allow us to conclude that the main host lattice excitation relevant to both the luminescence processes mentioned above is a very mobile excitonic excitation including a photon phase and the self- trapped exciton in its composition. The photon phase, as we suppose, represents a free exciton luminescence at room temperature. In this phase, via multiple reabsorption in the low-ene…

Solution processable high band gap hosts based on carbazole functionalized cyclic phosphazene cores for application in organic light‐emitting diodes

2011

A new class of solution processable dendrimers based on cyclic phosphazene (CP) cores have been prepared and used as host materials for blue and green organic light emitting diodes (OLEDs). The dendrimers are prepared in high yield from minimal step reactions, are soluble in common solvents for solution processing, are amorphous, and have excellent thermal properties necessary for application in OLEDs. OLED efficiencies of 10.3 cd/A (4.2 Im/W) and 35.3 cd/A (33.5 Im/W) were achieved using commercially available Flrpic and Ir(mppy) 3 as blue and green phosphorescent emitters, respectively. These efficiencies were 2x higher than control devices prepared using poly(N-vinylcarbazole), the most …

Design and photophysical properties of zinc(II) porphyrin-containing dendrons linked to a central artificial special pair.

2011

The click chemistry synthesis and photophysical properties, notably photo-induced energy and electron transfers between the central core and the peripheral chromophores of a series of artificial special pair-dendron systems (dendron = G1, G2, G3; Gx = zinc(II) tetra-meso-arylporphyrin-containing polyimides) built upon a central core of dimethylxanthenebis(metal(II) porphyrin) (metal = zinc, copper), are reported. The dendrons act as singlet and triplet energy acceptors or donors, depending on the dendrimeric systems. The presence of the paramagnetic d(9) copper(II) in the dendrimers promotes singlet-triplet energy transfer from the zinc(II) tetra-meso-arylporphyrin to the bis(copper(II) por…

Charged Bis-Cyclometalated Iridium(III) Complexes with Carbene-Based Ancillary Ligands

2013

Charged cydometalated (CN) iridium(III) complexes with carbene-based ancillary ligands are a promising family of deep-blue phosphorescent compounds. Their emission properties are controlled primarily by the main CN ligands, in contrast to the classical design of charged complexes where NN ancillary ligands with low-energy pi* orbitals, such as 2,2'-bipyridine, are generally used for this purpose. Herein we report two series of charged iridium complexes with various carbene-based ancillary ligands. In the first series the CAN ligand is 2-phenylpyridine, whereas in the second one it is 2-(2,4-difluorophenyl)-pyridine. One biscarbene (:CC:) and four different pyridine carbene (NC:) chelators a…

White-light phosphorescence emission from a single molecule: application to OLED.

2009

A simple mononuclear cyclometallated iridium(III) complex exhibits white photo- and electro- luminescence in the wavelength range from 440 to 800 nm, which originates from a single emitting excited state of mixed character. Bolink Henk, Henk.Bolink@uv.es ; Coronado Miralles, Eugenio, Eugenio.Coronado@uv.es

Low-temperature phosphorescence of 1,4-benzodiazepines

1991

Abstract A highly sensitive method for the low-temperature phosphorescence determination of a series of 1,4-benzodiazepines has been developed. Oxazepam has been used as a test molecule to study the effects of instrumental parameters, such as time decay, gate time, excitation and emission slits, and ordinate, on the phosphorescence spectra. The corresponding analytical parameters have been established for different concentration levels. Under the best sensitivity conditions a limit of detection of 16 parts per trillion (ppt) for oxazepam, 3.8 ppt for medazepam, 2 ppt for prazepam, 5 × 10 −3 ppt for diazepam, and 0.09 ppt for lorazepam could be obtained. The proposed method is thus the most …

Theoretical studies on the spectroscopy of the 7-azaindole monomer and dimer

2001

The absorption and the emission spectra, both fluorescence and phosphorescence, of the 7-azaindole molecule have been studied by means of the complete active space (CAS) SCF method and multiconfigurational second-order perturbation theory (CASPT2). Excitation energies, oscillator strengths, dipole moments, transition dipole moments, and their directions have been computed and the results compared to those of analogous molecules such as indene, indole, and benzimidazole, to get a homogeneous picture of the photophysics of the systems. The absorption and emission of the 7-azaindole dimer and its related tautomer have also been computed in order to get further insight into the double fluoresce…

Toxicity assessment of pesticides using the microtox test: application to environmental samples.

1997

The photophysics and photochemistry of cofacial free base and metallated bisporphyrins held together by covalent architectures

2007

Abstract This review focuses on the photophysical properties of bisporphyrin systems held in a face-to-face configuration by covalent bonds via flexible or rigid spacers and metal–metal bonds. The cofacial arrangement induces intramolecular bismacrocycle interactions promoting basic photophysical events such as excitonic interactions and energy and electron transfers. These events are relevant to mimic light harvesting and reactor devices known for photosynthesis in plants, and can be monitored by luminescence and flash photolysis methods.

Cietvielu luminoforu molekulārais dizains

2022

Cietvielu luminoforu molekulārais dizains. Mazarevičs A., zinātniskie vadītāji Mg. chem. Leduskrasts K., Prof., Dr. chem. Sūna E. Maģistra darbs, 72 lapaspuses, 44 attēli, 11 tabulas, 38 literatūrās avoti, 1 pielikums. Latviešu valodā. Literatūras apskatā analizēti organiskie luminofori, luminiscence un fosforescence. Iekļauti organiskās fosforescences iegūšanas metožu piemēri izmantojot starpmolekulāru mijiedarbību veidošanu, smagā atoma efektu, kā arī heteroatomu ievadīšanu molekulā. Rezultātu izvērtējumā aprakstīta sintezēto savienojumu iegūšana un analizētas to luminiscentās īpašības. Eksperimentālajā daļā sintezēti 26 savienojumi, no kuriem luminiscentās īpašības noteiktas 13. No lumin…