Cerium-doped yttrium aluminate-based phosphors prepared by wet-chemical synthesis route: Modulation of the luminescence color by changing the host-lattice composition

Cerium activated yttrium aluminate with garnet structure Y3Al5O12:Ce3+ is used as yellow emitting phosphor for the manufacturing of white light emitting diodes (WLEDs) generating “cold white” illumination. The luminescent emission of WLEDs can be either red, or blue tuned by the partial substitution of Y3+ with Gd3+ and/or Al3+ with B3+, respectively. The paper presents our results referring to the preparation of (Y,Gd)3(Al,B)5O12:Ce3+ type phosphors by the wet chemical synthesis route – WCS, using the simultaneous reagent addition technique – SimAdd. In this respect, the Y/Gd–Al/B–Ce precursors were obtained by coprecipitation, from Y, Gd, Al, Ce nitrates, boric acid and urea solution. The precursor nano-powders were intimately mixed with NH4Cl (flux), and heat treated at 1200 °C/2 h in nitrogen atmosphere. Based on complementary investigations it can be seen that the phosphorus composition consists of a mixture of (Y,Gd)3Al5O12:Ce3+ and (Y,Gd)BO3:Ce3+. The photoluminescent, morphological and structural properties of the phosphor powders were investigated in relation with the Gd/Y or B/Al substitution. It is revealed that the WCS-SimAdd route can be used to synthesize a phosphor with modulated color, appropriate for the use in LED-type optoelectronic devices.