Search results for "Phosphor"
showing 10 items of 1952 documents
Pyroelectric activity of LiGaO2, Li2GeO3, Li2B4O7 and LiNbO3 crystals: Pyroelectric luminescence and excitation of cathodoluminescence in scintillato…
2020
Abstract Basing on results of electric, spectral and kinetic measurements of spontaneous luminescence caused by cooling/heating in pyroelectric crystals LiGaO2, Li2GeO3, Li2B4O7 and LiNbO3 a mechanism of pyroelectric luminescence is proposed. Series of experiments were undertaken attaching a scintillating phosphor ScPO4 to a pyroelectric crystal and subjecting a pair of the bounded crystals to cooling/heating process. Pyroelectric activity causes not only pyroluminescence in pyroelectric crystals but also luminescence in a ScPO4, which is characterized with high intensity and kinetic and spectral properties typical for the intrinsic luminescence of a scintillator.
Solution-processable green phosphorescent iridium(III) complexes bearing 3,3,3-triphenylpropionic acid fragment for use in OLEDs
2018
New solution-processable materials based on well-known green iridium(III) heteroleptic complexes (ppy) 2 Ir(acac) and (ppy) 2 Ir(pic) were acquired by chemical modification of ppy ligand with functionable hydroxyl groups and subsequent esterification with 3,3,3-triphenylpropionic acid fragment. Photoluminescence quantum efficiencies up to 0.90 were measured for the compounds in solution. Emission characteristics in pure solid films and different guest-host systems with hole transporting materials were investigated. Green light emitting OLEDs (organic light emitting devices) was prepared and characterized.
Photostimulated luminescence properties of neutron image plates
2016
Abstract The luminescence properties of two commercial neutron-sensitive image-plates based on Gd 2 O 3 -doped BaFBr:Eu 2 + storage phosphors are examined. These are white Fuji plates and blue Fuji plates (BAS-ND) with Gd 2 O 3 content by weight of 34% and 50%, respectively. Both plates show two maxima in the photostimulation spectrum near 500 nm and 600 nm, with the ratio of the peak responses ( I 600 nm / I 500 nm ) 1.39 and 0.53 for the white and blue plates respectively. The optimum wavelengths for photostimulation for the two phosphors are therefore different. The response of the blue plate is only 25% that of the white plate, if each is stimulated at its optimum wavelength.
Platinum( ) and palladium( ) complexes with electron-deficient -diethoxyphosphorylporphyrins: synthesis, structure and tuning of photophysical prope…
2019
The luminescence quenching by O and photodegradation of Pt( ) and Pd( ) phosphorylporphyrins are reported.
Ein neuartiges Verfahren der Sauerstoffdetektion für Medizin, Biologie, Umweltforschung und Biotechnik auf Basis der Lumineszenzlöschung - An Innovat…
1996
For most (aerobic) animal organisms, oxygen is a mandatory and global substrate. The accurate measurement of oxygen is therefore of importance in the fields of medicine, biology, environmental research and biotechnology. The fact that oxygen is not readily soluble in aqueous media makes its detection more difficult. In contrast to the technique of polarography, the use of luminescence quenching by paramagnetic oxygen, does not consume the oxygen. Another problem of oxygen detection in connection with respiration is the need for very short response times. A third problem, which is associated with luminescence itself, is the fading of the dyes, which results in long-term signal instability. T…
Luminescence of phosphorus doped silica glass
2017
This work is supported by Material Science program IMIS2 of Latvia.
Low Current Density Driving Leads to Efficient, Bright and Stable Green Electroluminescence
2013
Electroluminescent devices have the potential to reshape lighting and display technologies by providing low-energy consuming solutions with great aesthetic features, such as flexibility and transparency. In particular, light-emitting electrochemical cells (LECs) are among the simplest electro-luminescent devices. The device operates with air-stable materials and the active layer can be resumed to an ionic phosphorescent emitter. As a consequence, LECs can be assembled using solution-process technologies, which could allow for low-cost and large-area lighting applications in the future. High efficiencies have been reported at rather low luminances (<50 cd m(-2)) and at very low current densi…
Determining efficacy of monitoring devices on ceramic bond to resin composite
2012
Objectives: This paper aims to assess the effectiveness of 3D nanoroughness and 2D microroughness evaluations, by their correlation with contact angle measurements and shear bond strength test, in order to evaluate the effect of two different acids conditioning on the bonding efficacy of a leucite-based glass-ceramic to a composite resin. Study Design: Ceramic (IPS Empress) blocks were treated as follows: 1) no treatment, 2) 37% phosphoric acid (H3PO4), 15 s, 3) 9% hydrofluoric acid (HF), 5 min. Micro- and nano-roughness were assessed with a profilometer and by means of an atomic force microscopy (AFM). Water contact angle (CA) measurements were determined to assess wettability of the ceram…
Studies of the Phosphatization of Steel and its Corrosion Products
1986
The reaction of phosphoric acid with steel is a basic process in many technological procedures. A typical example is the pretreatment of steel surfaces for the application of coatings. The aim of the treatment is to clean the surface, to produce a homogeneousr tight, and smooth cover and to provide a reliable adhesion between the steel substrate and the coating. This example points out that the phase composition of the layer formed is of great interest, and that reactions with residues on the surface, such as oxides and corrosion products, have to be considered, too. The same holds for phosphate layers formed in order to modify the mechanical or corrosion behavior of steel surfaces. Because…
Photophysical and electroluminescence properties of bis(2′,6′-difluoro-2,3′-bipyridinato-N,C4′)iridium(picolinate) complexes: effect of electron-with…
2015
Herein, we have synthesized a series of 2′,6′-difluoro-2,3′-bipyridine cyclometalating ligands by substituting electron-withdrawing (–CHO, –CF3, and –CN) and electron-donating (–OMe and –NMe2) groups at the 4′ position of the pyridyl moiety and utilized them for the construction of five new iridium(III) complexes (Ir1–Ir5) in the presence of picolinate as an ancillary ligand. The photophysical properties of the developed iridium(III) compounds were investigated with a view to understand the substituent effects. The strong electron-withdrawing (–CN) group containing the iridium(III) compound (Ir3) exhibits highly efficient genuine green phosphorescence (λmax = 508 nm) at room temperature in …