White Light Generation in Rare-Earth-Doped Amorphous Films Produced by Ultrasonic Spray Pyrolysis

Abstract:

Aluminium and hafnium oxide films doped with CeCl₃/TbCl₃/MnCl₂ were deposited at 300 °C by ultrasonic spray pyrolysis. The films analysed by X-Ray diffraction exhibit a very broad band typical of amorphous materials. Non-radiative energy transfer from Ce³⁺ to Tb³⁺ and Mn²⁺ is observed upon UV excitation at 280 nm (peak emission wavelength of AlGaN-based LEDs). Such energy transfer gives place to a simultaneous emission of the donor and acceptor ions in the blue, green, yellow and red regions, resulting in cold white light emission, with chromaticity coordinates and colour temperatures: (0.30,0.32) and 7300 K (AOCTM film), and (0.32,0.37) and 6400 K (HOCTM film). Thus, this type of thin films might contribute to the development of efficient AlGaN-based LEDs pumped phosphors for cold white light generation.

• Periodical: Advances in Science and Technology (Volume 82)
• Pages: 19-24
• DOI: https://doi.org/10.4028/www.scientific.net/AST.82.19
• Online since: September 2012
• Authors: Rafael Martínez-Martínez, Edgardo Yescas, Enrique Álvarez, Ciro Falcony, Ulises Caldiño
• Keywords: Al₂O₃, Ce³⁺, Film, HfO₂, Mn²⁺, Nonradiative Energy Transfer, Photoluminescence (PL), Tb³⁺

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