Photoluminescence, recombination induced luminescence and electroluminescence in epoxy resin

Abstract

This is the unspecified version of the paper.This version of the publication may differ from the final published version. Permanent repository link ABSTRACTDielectric breakdown of epoxies is preceded by light emission, or so-called electroluminescence, from the solid-state material. Very little is known about the luminescence properties of epoxies. The aim of this paper is to derive information that can be used as a basis to understand the nature of the excited states and their involvement in electrical degradation processes. Three different kinds of stimulation were used to excite the material luminescence. Photoluminescence was performed on the base resin, the hardener and the cured resin. Luminescence excited by a silent discharge has been analysed to identify which of the luminescent centres are optically active upon the recombination of electrical charges and could therefore act as charge traps. Finally, the electroluminescence spectrum has been acquired and compared with the previous ones. Although the identification of the origin of these emissions is far from being complete, it has been found that the photoluminescence from the cured resin is due to in-chain chromophores, which acts as trapping centres. The excited states involved in photoluminescence also seems to be involved in electroluminescence, but other components are detected as well, which could be due to the degradation of the resin molecule under the effect of the electric stress.2

Properties of cathodoluminescence for cryogenic applications of SiO2-based space observatory optics and coatings

“…In addition, recent charging studies at Utah State University (USU) using low-flux intermediate-energy electron beams on thin film highly disordered SiO 2 samples exhibited not only cathodoluminescent behavior 3,11-14 but also occasional arcing under some conditions. Similar behavior was also observed in experiments for other dielectric materials including cyanate ester and epoxy resins in graphite and fiberglass composites 2,9 and Kapton HN TM polyimide and carbon-loaded polyimide nanodielectric composites 2,13 . These results suggest that materials used in structural components, optical elements, and thermal control surfaces of spacecraft and space-based observatories could, when exposed to the space plasma environment, luminesce.…”

Nanodielectric properties of high conductivity carbon-loaded polyimide under electron-beam irradiation

“…Charging studies on polymers and carbon composites have revealed that sample arcing and luminescence occur as a result of electron beam bombardment [3][4][5]. Both insulating regions and electrically isolated carbon particles (floating conductors) can accumulate and dissipate charge; cathodoluminescence results from the insulating polyimide regions.…”

Temporal and Spatial Correlations in Electron-Induced Arcs of Adjacent Dielectric Islands

“…Two forms of electron-induced light emission have been commonly encountered, both of which emit light from large surface areas that have been charged by the incident electron flux [4,5]. Continuous emission observed whenever a material is exposed to electron fluxes is termed "glow," or more properly, cathodoluminescence (CL) [4,[6][7][8]. Intermediate-duration light emissions events, which start with a large rapid spike in intensity similar to arcs and are followed by an exponential decay (~10-100 s decay constant) back to the continuous equilibrium CL intensity, have also been observed for several polymeric and composite materials [1,5].…”