In this study, the phosphors used in CRTs are coated with In2O3 conductive layer derived from the hydrolysis of indium chloride. The conductive coating retards/eliminates charging-up on the phosphor surface during the bombardment of the electrons and improves the cathodoluminescent brightness of the phosphor. However, the non-emissive conductive coating also degrades the cathodoluminescent brightness when it is too thick. The cathodoluminescent brightness increases initially with the amount of coating, reaches a maximum at 10 wt.% InCl3, and decreases with further increase of coating. It is found that with a 10 wt.% InCl3 coating, the brightness of phosphor increases by 20% at 500 V and 1 mu A. (c) 2004 Published by Elsevier B.V.