Zhang S, Tan CS, Wong TKS, Su H, Teo RJW. Opto-impedance spectroscopy and equivalent circuit analyses of AC powder electroluminescent devices.
OPTICS EXPRESS 2017;
25:A454-A466. [PMID:
28788826 DOI:
10.1364/oe.25.00a454]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
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.
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