Improved photoluminescence intensity and thermal stability brought by increasing Eu3+ content in KBaY1−xEuxSi2O7 solid-solution phosphors

Abstract

Developing high brightness, high color purity and thermal stable red phosphors has gained an increasing attention for enhancing the performance of white light emitting diodes (w-LEDs). Herein, a series of red-emitting KBaY1−xEuxSi2O7 (0 < x < 1) solid-solution phosphors were designed and fabricated. The phosphors can be excited by 394 nm near-UV light and emit red light peaking at 612 nm due to the 5D0 → 7F2 transition of Eu3+. The increasing proportion of Eu3+ in the solid-solution system can improve the photoluminescence intensity and thermal stability of the phosphors continuously until the Eu3+ concentration comes to 100%, while no deformation of the crystal structure has been brought. The as-prepared KBaEuSi2O7 phosphor shows excellent thermal photoluminescence stability, its emission integrated intensity can still maintain ∼90% of the initial value at room temperature when heating to 180 °C. The CIE coordinates (0.652, 0.348) of KBaEuSi2O7 phosphor are very close to the NTSC (National television system committee) standard red chromaticity (0.67, 0.33), and the color shift at high temperature is very slight. The KBaEuSi2O7 phosphor can be regarded as a promising red luminescence candidate for w-LEDs.