ZnS:Mn,Cu粉末直流电致发光(DCEL)器件在交流(AC)电压下的频率特性

本文研究了DCEL器件在AC条件下,亮度、效率、有功电流、无功电流及损耗角正切与频率的关系.指出了发光区有效电场强度、发光区的宽度及电压分配系数等都是与频率有关的物理量.证明了有功电流和损耗角正切随频率的变化可分为两个区,在低于1kHz的低频区,有功电流和介质损耗分别以漏导电流和漏导损耗为主,可称为漏导电流区.在大于1kHz的高频区,有功电流中与各种松弛极化形式有关的吸收电流占主导且随频率增加较快.与其相关的,和各种极化有关的介质损耗急剧增加并超过漏导损耗而成为损耗的的主要成分,从而导致发光效率下降.这一区域可称为吸收电流区.

FREQUENCY CHARACTERISTICS OF POWDER ZnS:Mn,Cu DIRECT CURRENT ELECTROLUMINESCENT(DCEL)DEVICES IN ALTERNATING CURRENT(AC)VOLTAGE OPERATION

In this paper,the investigation on brightness(B),efficiency(η),capacit-ivc currant(IC),loss current(IR)and dielectric loss angle tangent(tgδ)of DCEL devices operated under AC voltage is reported.The results indicate that the effective electric field(E),the width of the emission region and the distribution rate in voltage are frequency dependent.It is concluded that the IR-f dependence can be divided into two regions,In the region of about 0-1kHz,IR increases slowly with increasing frequency and tgδ-f dependence is in accordance with that of leak conduction current loss in dielectric.This means that the dominant part of IR in 0-1kHz region is leakege current.This region can be called leakege current region.In the region above 1 kHz,the increase of IR with raising frequency becomes quicker and tgδ-f dependence tends to be steady.This suggests that IR be dominanted by absorption current relative to polarization of dielectric.This region can be called absorption current region.In this region dielectric loss increases rapidly and luminescence efficiency is on the decrease.