Nanocrystalline europium hexaboride: A new type efficient activator enhanced in photoluminescent of CaNb2O6:Eu3+ phosphor

Abstract A novel alkaline earth niobates red phosphor CaNb2O6:Eu3+ have been prepared through solid-state reaction, using the nanocrystalline EuB6 as a novel activator. The Rietveld refinement of XRD results reveal that the Eu3+ ions substitute the lattice site of Ca2+ ions and the B2− ions replace the lattice site of O2− ions, which induces the defect energy levels at the band gap of 5Dn levels and leads to higher luminescence intensity of five times higher than using the Eu2O3 activator. The CIE chromaticity coordinates of Ca0·88Nb2O6:0.12EuB6 phosphor were calculated to be (0.643, 0.34) and it is quite similar to that of pure red light. Moreover, this phosphor exhibits an excellent luminescence thermal stability. When the ambient temperature rises to 398 K (125 °C) and 423 K (150 °C), the integrated emission intensity remains 90% and 86% of their initial PL intensity at 300 K, respectively. Based on above mentioned, the Ca1-xNb2O6:xEuB6 as a NUV-excited red phosphor have a potential application for the high-performance white LEDs.