ORIGINAL PAPER Cathodoluminescence properties of Pr 3+ -doped perovskite-type transparent red luminescent thin films processed by a sol–gel method Yohei Ishikawa • Tomokatsu Hayakawa • Koji Inoue • Masayuki Nogami Received: 12 June 2012 / Accepted: 13 December 2012 / Published online: 3 January 2013 Ó Springer Science+Business Media New York 2012 Abstract Transparent, luminescent films of Pr 3? -doped (Ca 0.6 Sr 0.4 )TiO 3 (CSTO) have been prepared for cathodo- excitation of pure red luminescence by a sol–gel method from a stabilized sol with Ca 2? , Sr 2? , Pr 3? ions and tita- nium-isopropoxide in acetic acid. The structure and surface morphology of the obtained films are characterized by X-ray diffraction and Atomic Force Microscopy, respec- tively. The photoluminescence and cathodoluminescence (CL) properties of the films are evaluated. The films exhibit a strong single line of 1 D 2 ? 3 H 4 red photoluminescence of Pr 3? ions doped, which increases almost linearly with the number of the dip-coated layers. It is also found that strong single red photoemission is observed and the CL intensity increases with increasing acceleration voltage. The results demonstrate that it is potential for application in field- emission display devices. Keywords Red luminescence Á Cathodeluminescence Á Pr 3? Á Perovskite Á Sol–gel 1 Introduction Oxide phosphors have been of great interest for various prospective applications of flat panel displays (FPDs), including liquid crystal displays (LCDs), plasma display panels (PDPs), light emitting diode (LED) displays, vacuum fluorescent displays (VFDs), field-emission displays (FEDs), and electroluminescent (EL) devices, because oxide phosphors present possible advantages of high chemical stability and efficient luminescent characteristics [1, 2]. Nevertheless, on display devices of glow-discharge type, such as cathode-ray tube (CRT) displays, it was difficult to express pure black color because most of oxide phosphors are in white powder. However, it will be overcome if a transparent luminescent thin film is adapted in the frame- work of FED: A dark-colored electrode/electron emitter such as carbon nanotube simultaneously expresses high-quality black color in OFF state, while electron emission in ON state irradiate a luminescent film so that visible light of red(R), green(G) or blue(B) is activated [3]. For the purpose, a high visible optical translucency is demanded against lumines- cent films. As for thin film, moreover, it is possible to reduce the thickness while keeping the flatness and smooth surface and thus the influence of the degasification becomes small due to the small specific surface area. Recently, rare-earth- doped perovskite-type phosphor powders and films of (Ca,Sr,Ba)TiO 3 have been studied [4–13] and some pre- liminary results have been obtained for highly brilliant (Ca 0.6 Sr 0.4 )TiO 3 (CSTO) phosphor [10, 14, 15]. In particu- lar, a red luminescence of Pr 3? ions has attracted scientific and technological interests. However there is still less report about cathodoluminescent performance of Pr 3? doped (Ca 0.6 Sr 0.4 )TiO 3 phosphor film as a FED device. Cathodo- luminescence (CL) is an optical and electrical phenomenon whereby a beam of electrons is generated by an electron gun. Electronic supplementary material The online version of this article (doi:10.1007/s10971-012-2939-8) contains supplementary material, which is available to authorized users. Y. Ishikawa Á T. Hayakawa (&) Á M. Nogami Field of Advanced Energy Conversion, Department of Frontier Materials, Nagoya Institute of Technology, Gokiso, Showa, Nagoya-city, Aichi 466-8555, Japan e-mail: hayatomo@nitech.ac.jp K. Inoue Mie Industrial Research Institute, 5-5-45, Takatyaya, Tsu-city, Mie 514-0819, Japan 123 J Sol-Gel Sci Technol (2013) 65:324–328 DOI 10.1007/s10971-012-2939-8