AC Electroluminescent Processes in Pr3+-Activated (Ba0.4Ca0.6)TiO3 Diphase Polycrystals

• Main Authors: Nan Gao, Min Zhang, Jun-Cheng Zhang
• Format: Article
• Language: English
• Published: MDPI AG 2017-05-01
• Series: Materials
• Subjects: powders; solid-state reaction; optical properties; functional applications
• Online Access: http://www.mdpi.com/1996-1944/10/5/565

We investigated the properties of alternating current (AC)-driven electroluminescence from (Ba0.4Ca0.6)TiO3:Pr3+ diphase polycrystal-based device. The results of crystal phases and micrographs, and the symmetrical dual emissions in one AC cycle, indicate the spontaneous formation of a dielectric/phosphor/dielectric sandwich microstructure in (Ba0.4Ca0.6)TiO3:Pr3+. The electroluminescent device emits a red light of 617 nm, which is attributed to the 1D2-3H4 transition of Pr3+ in the phosphor phase. At a fixed AC frequency, the intensity of electroluminescence exhibits a steep enhancement when applying an increased driving electric field that is beyond a threshold. In a fixed driving electric field, the intensity of electroluminescence shows a rapid rise at low frequencies, but reaches saturation at high frequencies. Based on a double-injection model, we discussed systematically the electroluminescent processes in a whole cycle of AC electric field, which matched well with the experimental data. Our investigation is expected to expand our understanding of such a diphase electroluminescent device, thereby promoting their applications in lighting and displays.