Abstract
A red-emitting phosphor Ca2.91Si2O7∶0.09Eu3+with partial Al3+/P5+substitution on Si4+was synthesized via a simple solid-state method,and the effects of the introduction of the M3+/5+(M=Al,P)ions on the crystal structure and photoluminescence performance of Ca2.91Si2-xMxO7∶0.09Eu3+phosphors were investigated.The X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),and X-ray photoelectron spectroscopy(XPS)results revealed that the structure of Ca3Si2O7 remained the same after the introduction of Al3+and P5+ions.The characteristic emission of Eu3+-doped Ca3Si2_xMxO7 phosphors exhibited two main peaks at 617 nm(red)and 593 nm(orange)under excitation at 394 nm,which originated from the 5D0 → 7F2 and 5D0 → 7F1 electron transitions of Eu3+ions.After the partial substitution of Al3+and P5+,the red emission intensities of the Ca2.91Si2O7∶0.09Eu3+phosphors were significantly enhanced by 1.88-and 1.42-fold,respectively,which is attributed to the crystal-field effect around Eu3+.Meanwhile,the luminescence intensities of the Ca2.91Si1.96 Al0.04O7∶0.09Eu3+and Ca2.91Si1.94P0.06O7∶0.09Eu3+phos-phors at 210 ℃ were 79.36％and 77.53％of those at 30 ℃,respectively,indicating their excellent thermal sta-bility.Moreover,the as-prepared Ca2.91Si1.96A-l0.04O7∶0.09Eu3+and Ca2.91Si1.94P0.06O7∶0.09Eu3+red-emitting phosphors were combined with a near-ultraviolet chip of 395 nm to fabricate red-light-emitting diode(LED)and white(w)-LED devices with excellent chromaticity features.In summary,Al3+/P5+-substituted Ca2.91Si2O7∶0.09Eu3+can serve as red-emitting phosphors for appli-cations in w-LEDs.
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