ZnS∶Cu粉末交流电致发光器件特性研究

以商用ZnS∶Cu交流电致发光粉作为发光层,以ITO作为电极制作了粉末交流电致发光器件。以交流脉冲方波为驱动电压,详细研究了外加电压的幅值,频率以及脉宽对其发光频谱及亮度的影响。实验结果表明当电压小于200 V,发光亮度随着电压的升高而缓慢增强,当电压大于200 V,随着电压的升高亮度准线性增强。随着驱动频率的增大,发光光谱的中心波长发生蓝移,从100 Hz时的504 nm(绿光)到100 kHz时的450 nm(蓝光),发光亮度随频率增加先快速增强然后逐渐趋于饱和,达到一个极值后开始减小。随着脉宽的增大,发光亮度线性增强。另外文章中对驱动频率影响发光光谱的原因进行了深入分析,这对进一步研究ZnS∶Cu交流电致发光粉的发光机理有着重要的作用。

An Investigation on AC Electroluminescent Properties of ZnS:Cu Powder

In order to study the electroluminescent properties of ZnS:Cu powder,we use commercial phosphors as electroluminescent materials and use ITO as electrodes to make the powder AC EL.We stud- y the electroluminescent properties of ZnS:Cu in different amplitude,frequency and duty cycle of the square signal,and find that along with the increase of amplitude of applied voltage,the luminance in- crease.A rise in the excitation frequency up to 100 kHz can produce two effects:an increase of the emis- sion intensity and a shift of the spectra which change from 504 nm at 100 Hz to 450 nm at 100 kHz.A rise in the duty cycle of the square signal results in an increase of the luminance.And along with the increase of pulse width,the luminance increase linearly.