One of the key factors that will determine the future success of field emission devices (FEDs) as a competitive technology in the flat panel display market is obtaining a red, green, blue (RGB) phosphor set that will satisfy a strict set of criteria. These criteria are imposed by at least three different sets of demands: (1) The RGB set must be capable of reproducing a color gamut close to the NTSC standard. (2) The chemical and physical properties of the phosphor set must be compatible with the cathode environment of the device. (3) The set must be efficient enough to equal or outperform competing flat panel technologies in terms of power consumption. In this paper a series of commercial and experimental phosphors is examined to assess their potential as candidates to satisfy some of the above demands. Over the last twenty years considerable effort has been expended in developing the high voltage (20 kV - 30 kV) phosphors used in television, special purpose CRTs and x-ray imaging. In spite of this, however, there is a relative paucity of information available on performance in the range 300 V - 1000 V. We present experimental results of luminous efficiencies of a range of phosphors as a function of excitation voltage and low voltage saturation results of some phosphors under FED working conditions to discuss the potential of these phosphors in field emission device environments.