Synthesis and characterization of cerium doped yttrium-gadolinium aluminate phosphors by wet-chemical synthesis route

Abstract

Synthesis of cerium activated yttrium gadolinium aluminate phosphors (Y,Gd)3Al5O12:Ce using the wet-chemical synthesis route via the reagent simultaneous addition technique (WCS-SimAdd) is reported for the first time. Y-Gd-Ce-Al precursors with variable Y:Gd ratios have been precipitated from metal nitrates and urea solutions that were simultaneously added, in an aqueous medium with controlled pH and temperature. The precursor nanopowders were intimately mixed with NH4Cl (flux) and calcined for 2 hrs at 1200C, in nitrogen flow and converted into micro-powders of phosphor with nominal formula Y2.97-xGdx Ce0.03 Al5O12 (where x=0; 0.75; 1.50; 2.25; 2.97). Chemical composition and thermal behaviour of precursors as well as the PL properties, and morphological and structural characteristics of phosphor powders were investigated in relation with the Gd amount. WCS-SimAdd route enables a good control of the synthesis conditions to prepare (Y,Gd)3Al5O12: Ce3+ phosphors with cubic/garnet crystalline structure, regular particle dimensions and shapes and intense yellow-to-orange emission appropriate for use in LED type optoelectronic devices.