Enhancing blue light absorption by Sm3+ Co-doing in Ca9Nd(PO4)7: Eu3+ for white light-emitting diodes

Abstract

White light-emitting diodes (WLEDs) is widely concerned as the next-generation source of displays and lighting on account of many advantages. In this work, Sm3+ ions were introduced into Ca9Nd(PO4)7: Eu3+ (CNPO: Eu3+) red phosphors as a co-dopant to boost the blue-light excitation. X-ray diffraction (XRD) data confirm the successful preparation of the materials. Rietveld refinements were employed to investigate the site occupation and lattice parameter variation. All obtained materials have showed red emission under blue light or near-ultraviolet light excitation. The photoluminescence (PL) emission spectra features both signals from the two dopants, and the introduction of Sm3+ could effectively boost the red-light emission and blue-light excitation. Theoretical simulations help evidence the capability of the CNPO materials as host matrix of luminescent centers. Finally, a blue LED chip-based WLED was assembled in demonstration of their potential applications. Compared to the controlling device made with Eu3+ single-doped samples, the co-doped one has stronger blue light excitation and red light emission that guarantees a high luminous efficacy of over 90 lm W−1. The device also shows a superb long-term stability under continuous working. All in all, the CNPO: Eu3+, Sm3+ phosphors have shown many promising aspects in blue chip-based WLED applications.