In this study, an orange-red silicate phosphor that is used in light emitting diodes (LEDs) was coated with a SiO2 blocking layer via a sol-gel reaction of tetra-ethyl ortho-silicate (TEOS) to investigate its reliability as an encapsulant. A sol-gel coating protects the phosphor surface from moisture and reactive materials and improves the reliability of the phosphor. The efficacy of the phosphor coating following an 85 degrees C and 85 relative humidity (Rh)% test decreased by 7%, whereas an uncoated phosphor coating decreased by 35%. A SiO2 sol-gel coating decreases the luminous efficiency by a small amount with each coating. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.