The effect of the carbon source on the optimization of the photoluminescence (PL) performance of boron carbon oxynitride (BCNO) phosphor particles was systematically investigated. Ethylene glycol, tetraethylene glycol (TEG), and poly(ethylene glycol) of various Mw values were used as the organic sources. When TEG was used, the BCNO phosphors exhibited high PL performance under excitation at 365 nm with a quantum efficiency of up to 60%. The emission spectrum peak of the prepared BCNO particles was affected by the Mw of the carbon sources. An additional study investigated in detail the effects of the carbon/boron and nitrogen/boron molar ratios on PL properties. The emission spectra with a wavelength peak ranging from 380 nm (near UV) to 570 nm (near red) could be adjusted by varying the carbon/boron or nitrogen/boron ratios. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3474941] All rights reserved.