Open AccessOpto-impedance spectroscopy and equivalent circuit analyses of AC powder electroluminescent devices
Author(s) -
Shuai Zhang,
Chuan Seng Tan,
Terence Kin Shun Wong,
Haibin Su,
Ronnie Jin Wah Teo
Publication year - 2017
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.25.00a454
Subject(s) - electroluminescence , materials science , phosphor , dielectric , optoelectronics , dielectric spectroscopy , optics , equivalent circuit , relaxation (psychology) , electrode , voltage , nanotechnology , chemistry , electrical engineering , physics , electrochemistry , psychology , social psychology , engineering , layer (electronics)
High energy photons can affect the dielectric response of AC powder electroluminescent devices (ACPELDs). In this paper, electroluminescent (EL), phosphor and dielectric films are photo-excited at peak wavelengths of 399 nm, 520 nm and 625 nm to identify the dielectric relaxation processes occurring in ACPELDs. The 399 nm illumination changes the frequency-dependent dielectric responses of both EL and phosphor films due to the photo-induced excitation of ZnS:Cu,Al phosphor particles. A higher illumination intensity increases the dipolar polarization in the resin matrix and enhances the Maxwell-Wagner-Sillars (MWS) effect at the particle/resin interfaces. Equivalent circuits relating to the relaxation processes present in the EL and phosphor films are derived. From the analyses of the circuit component values, a charge generation and accumulation process is proposed to explain these opto-impedance behaviors.