Orange-red-emitting Sm3+-doped double perovskite CaY0·5Ta0·5O3 phosphor with highly thermal stability for white LED applications

Abstract

The novel orange-red-emitting CaY0·5Ta0·5O3:xSm3+ phosphors (x = 0.01–0.30) with double perovskite structures are prepared by a solid-state reaction. X-ray diffraction (XRD) patterns, photoluminescence, thermal quenching mechanism, and decay curves of the phosphors are discussed. The CaY0·5Ta0·5O3:Sm3+ phosphor shows the orange-red emission (603 nm) under 407 nm excitation. The photoluminescence (PL) spectra of CaY0·5Ta0·5O3:Sm3+ phosphor are ascribed to the 4G5/2 to 6HJ (J = 5/2, 7/2, 9/2, and 11/2). The quenching concentration of CaY0·5Ta0·5O3:Sm3+ phosphor is approximately 2 mol%. The quenching temperature for CaY0·5Ta0·5O3:0.02Sm3+ is estimated more than 500 K, indicating the products have excellent thermal stability. The temperature-dependent luminescence intensity ratio (I650 nm/I603 nm) of CaY0·5Ta0·5O3:0.02Sm3+ phosphor is discussed. The electroluminescence (EL) spectrum of the packaged red LED is similar to the PL spectrum of CaY0·5Ta0·5O3:Sm3+ phosphor. The CIE coordinates of the packaged white LED are (0.307, 0.335), which approach the equal energy white light. Therefore, Sm3+-doped CaY0·5Ta0·5O3 phosphors have a promising application in white light-emitting diodes.