Electroluminescent Lines in ZnS Powder Particles

Abstract

Several new embedding media of the same refractive index as ZnS are described which make possible the microscopic examination of the interior of electroluminescent particles taken from efficient industrial lots. Light is emitted in form of lines or striations extending through most of the diameter of the particles. The brightness of single lines has been measured in dependence of applied voltage, frequency, phase, and position along the line. Evidence is presented that the EL lines are associated with invisible copper-sulfide-decorated, conducting imperfection lines of submicroscopic diameter, and that coarse, visible imperfections are not the cause of EL.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.122.253.228 Downloaded on 2015-05-27 to IP ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.122.253.228

Transient Electroluminescence from Poly(phenylenevinylene)-Based Devices

“…The EL spectrum associated with these spikes (not shown here) is very similar to the regular EL spectrum of PPV. These observations are similar to the so-called out-of-phase EL spikes observed in the blue EL emitted by ZnS:Mn thin-film devices [89] and in ZnS:Cu powder phosphors dispersed in dielectric.…”

Microstructure and electroluminescence of ZnS:Cu,Cl phosphor powders prepared by firing with CuS nanocrystallites

“…On the basis of the previous studies [12,13] and results shown above, EL has been attributed to the ionization of activators by the impact of charge carriers accelerated by the high electric fields between Cu x S precipitates and ZnS:Cu,Cl matrix. It is believed that both the amount as well as the physical properties of Cu x S precipitates would influence the recombination rate and the following EL intensity.…”

“…According to the bipolar field emission model proposed by Fischer [12,13], conductive impurities such as cuprous sulfides (Cu x S) are necessary for luminescent ZnS particles to intensify the electric field, and to allow holes and electrons to recombine with radiation in luminescent centers. Therefore, by referring to the XRD analysis shown above, we can also predict that the samples fired at 900 • C with Cu Figure 3 shows the EL emission spectra of ZnS:Cu,Cl powders with various amount of Cu addition.…”

Synthesis and characterization of Zn1−xCdxS:Cu, Cl red electroluminescent phosphor powders

“…The mechanism of high-field EL was proposed to result from the intensification of the electric field near a ZnS-Cu x S contact, and the induction of the tunneling charge carriers to activate the luminescence centers, e.g. Cu, Mn [2,3]. The precipitated Cu x S phase, which has been observed by Ono et al [4] and our group [5] by electron microscopy and optical analysis, is crucial to EL emission.…”