An Analysis of ZnS:Cu Phosphor Layer Thickness Influence on Electroluminescence Device Performances

Electroluminescence (EL) device is a new technology; its thickness is within micrometer range which can bend more easily and emit light. However, the thickness of ZnS:Cu phosphor layer may affect the light intensity, so we have analyzed the thickness of ZnS:Cu phosphor layer on EL device. The EL devices consist of ITO:PET/ZnS:Cu phosphor/insulator (BaTiO3)/Ag electrode. The EL devices were fabricated in changing thickness 10 μm, 30 μm, and 50 μm. At 100 V 400 Hz, the luminance of EL devices was 51.22 cd/m2 for thickness 30 μm more than that of 45.78 cd/m2 (thickness: 10 μm) and 42.58 cd/m2 (thickness: 50 μm). However, the peak light intensity was achieved at wavelength of 507 nm which was not influenced by the thickness of the ZnS:Cu phosphor. The use of the ZnS:Cu phosphor layer at thickness 30 μm in the EL device significantly improves the luminescence performance.