A new single-component KCaY(PO4)(2):Dy3+, Eu3+ nanosized phosphor with high color-rendering index and excellent thermal resistance for warm-white NUV-LED

摘要

In this study, novel KCaY(PO4)(2):Dy3+, Eu3+ (KCYP:Dy3+, Eu3+) nanophosphor has been successfully prepared by a facile solution-combustion route. The crystal structure, morphological and microstructural features, and photoluminescence (PL) properties of KCYP:Dy3+, Eu3+ nanophosphor, as well as its thermal properties, have been studied. Investigations based on XRD, FTIR and Raman verify the formation of single-phased and well-crystallized KCYP:Dy3+, Eu3+. SEM and TEM observations reveal that the KCYP: Dy3+, Eu3+ nanophosphor displays uniform spherical morphology with an average particle size of about 47 nm. The optimal concentrations of Dy3+ and Eu3+ ions in KCYP were determined to be 3 mol% and 7 mol%, respectively. Under near-ultraviolet (NUV) excitation, individual Dy3+- or Eu3+-doped samples exhibit characteristic PL emissions in their respective regions. As for the Dy3+, Eu3+ co-doped KCYP, energy transfer has been confirmed happening from Dy3+ to Eu3+ via an electric dipole-dipole interaction, and the critical distance (R-c) was calculated to be 17.07 angstrom. Our experiments reveal that it is easy to produce warm white or tunable emissions by regulating the Eu3+ content. Moreover, the single-component KCYP:3%Dy3+, 7% Eu3+ nanosized phosphor has a very low correlated color temperature (2766 K) and a high color-rendering index (R-a = 81.6). The quenching temperature (T-0.5) of the KCYP: Dy3+, Eu3+ nanophosphor was found to be higher than 220 degrees C, indicating its superior thermal resistance. Consequent three rounds of the heating-cooling cycle experiments demonstrate no occurrence of thermal degradation. These findings suggest that this nanophosphor is a promising candidate for application in NUV-pumped glareless warm-white LED.