Cold white light generation through the simultaneous emission from Ce3+, Dy3+ and Mn2+ in 90Al2O3·2CeCl3·3DyCl3·5MnCl2 thin film

The photoluminescence of a CeCl3, DyCl3 and MnCl2 doped aluminum oxide film deposited by ultrasonic spray pyrolysis was characterized by excitation, emission and decay time spectroscopy. A nonradiative energy transfer from Ce3+ to Dy3+ and Mn2+ is observed upon UV excitation at 278 nm (peak emission wavelength of AlGaN-based LEDs). Such energy transfer leads to a simultaneous emission of these ions in the blue, green, yellow and red regions, resulting in white light emission with CIE1931 chromaticity coordinates, x=0.34 and y=0.23, which correspond to cold white light with a color temperature of 4900 K.