Nonlinear Electrical Properties of Thin Films of a Light-Emitting Perovskite-Type Oxide Pr0.002(Ca0.6Sr0.4)0.997TiO3

Double-insulating thin film type electroluminescent (EL) devices based on Pr0.002(Ca0.6Sr0.4)0.997TiO3 (PCSTO) and developed by Takashima et al. [Adv. Mater. 2009; 21; 3699-3702] emits pure red light with the wavelength λ = 610 nm under application of remarkably small voltage less than 10 Vrms. Since PCSTO is a perovskite-type oxide being chemically and thermally stable, the discovered small-voltage EL phenomenon may open a new application field of inorganic EL devices. Clarification of the EL mechanism will provide guidelines for improving the EL efficiency, which is a key of commercialization. As the first step on this way, PCSTO films sandwiched directly by electrodes have been prepared and their nonlinear electrical properties have been analyzed. In addition, EL from these metal-insulator-metal type devices has been detected and a preliminary discussion about it has been made.