Fabrication of Thick Film Inorganic EL Device by Co-firing Method

In order to determine the optimum fabrication condition of inorganic electroluminescence device by co-firing of multilayers consisted of phosphor ((Ca0.6Sr0.4)0.997Pr0.002)TiO3, dielectric materials BaTiO3, transparent electrode ITO and back electrode AgPd, sintering behavior of the layers and changes of chemical composition and electro-properties were investigated during calcination and co-firing. It was developed that the calcination temperature above 900°C was appropriate for the phosphor to suppress the crack and delamination caused by gas evolution and expansion during co-firing. Addition of phosphor material to BaTiO3 layer was an effective method to obtain the desired sintering behavior and electro-characteristics. The sintering behavior of BaTiO3 layer could be matched with that of phosphor layer, and dielectric constant was improved rather than BaTiO3 alone when BaTiO3 was mixed with phosphor with the volume ratio of 80 : 20. By co-firing at the temperatures of 800°C and 1100°C, the inorganic electro-luminescence device with the radiation of red light could be prepared.