Single-phased Y-2-xSi(3)O(3)N(4):xCe(3+) (0 < x <= 0.4) phosphors were prepared by solid-state reaction method in flowing hydrogen and nitrogen mixture gas. The X-ray diffraction analysis indicated that Ce3+ ions had been incorporated into the host lattice of Y2Si3O3N4, and the optimized doping concentration was 3 mol%. Strong absorption peaking at about 397 nm was observed on the excitation spectra for the Ce3+-doped phosphors, which matched well with the current near-ultraviolet (NUV) InGaN/GaN light emitting diodes (LEDs). The Y2-xCexSi3O3N4 samples showed a broad emission band with peak wavelength ranging from 465 to 500 nm, which was attributed to the 5d-4f transition of Ce3+. Energy transfer between Ce3+ ions was discussed and evidenced in detail, which resulted in redshift of the emission and concentration quenching. To understand the thermal quenching behavior, the temperature-dependent luminescence of Y1.94Ce0.06Si3O3N4 was investigated. Bluish-green LEDs was fabricated by integrating a near-ultraviolet (NUV) chip with Y1.94Si3O3N4:0.06Ce(3+) phosphor as a single package. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.006204jes] All rights reserved.