Ag@(Y0.95Eu0.05)(2)O-3 nanocomposites were synthesized by single step Ultrasonic Spray Pyrolysis (USP). 800 degrees C synthesis temperature and 1.5 l/min air flow were determined as optimal USP parameters. A detailed parametric study was conducted on samples with varying silver contents and heat treatment conditions. The effect of silver in both as prepared and heat treated samples were elucidated in terms of structural and functional properties. Ag incorporation decreased luminescence efficiency due to the lack of crystallization of matrix and non-homogenous distribution of Eu and Ag in as prepared samples. Heat treatment improved luminescence by improved crystal quality for all samples; however, with increasing Ag content effect of heat treatment was more pronounced owing to uniform distribution of Ag. 2.5 wt% Ag addition followed by 2 h heat treatment after USP synthesis is suggested as the most efficient nanocomposite for red light emitting down converting phosphor applications. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.