A novel red phosphor Ca₂YNbO₆:Eu³⁺ for WLEDs

Abstract

Due to the advantages of good physicochemical properties, thermal stability, and optical properties, double perovskite compounds have received extensive attention. On this basis, a new type of red phosphor, Ca2YNbO6:xEu3+, was synthesized using a high‐temperature solid‐phase method. Its phase purity, morphology, elemental composition, absorption spectrum, photoluminescence, thermal stability, and Commission Internationale de l'éclairage (CIE) chromaticity coordinates were thoroughly investigated. The results display that there is no impurity phase in the samples and the convergence factor Rwp = 14.2%; the microscopic particles are uniform and full, and the distribution of each element is uniform. The energy band gap ΔE is between 3.71 eV and 3.65 eV. The luminescence intensity is the best when the doped Eu3+ concentration x reaches 0.4, and emits 612 nm red light (5D0→7F2) under 465 nm excitation, and the concentration quenching is attributed to a d–d interaction. The luminescence intensity at 425 K was still 75% of the room temperature luminescence intensity, which indicates that the thermal stability is extremely superior. The CIE chromaticity coordinates (0.6534, 0.3455) of the Ca2YNbO6:0.4Eu3+ phosphors are very close to National Television Standards Committee (0.670, 0.330), and the samples have low correlated colour temperature (2656 K) and high colour purity (99.90%). All findings suggest that Ca2YNbO6:Eu3+ can serve as a substitute for red phosphor in WLEDs.

Excitation-Wavelength- and Time-Dependent Fluorescent Ink Based on RGB Building Blocks for Advanced Anti-Counterfeiting

“…For Ca 2 YNbO 6 :0.4Eu 3+ (Figure 1a), the ionic radius of Eu 3+ is 0.947 Å for six coordination, and it tends to replace the position of the Y 3+ ion after entering the matrix lattice, mainly due to having the same valence as Y 3+ and a similar ionic radius to Y 3+ (CN = 6, r = 0.900 Å). The replacement of Eu 3+ by Y 3+ was also confirmed by Shi et al in Ca 2 YNbO 6 [7]. For SrAl 2 O 4 :0.01Eu 2+ , 0.02Dy 3+ (Figure 1b), the ionic radii of Sr 2+ , Al 3+ , Eu 2+ and Dy 3+ are 1.180 Å, 0.535 Å, 1.170 Å and 0.912 Å for six coordination, respectively.…”

Eu3+ Site Distribution and Local Distortion of Photoluminescent Ca3WO6:(Eu3+, K+) Double Perovskites as High‐Color‐Purity Red Phosphors

“…Here, we attempt to assess the CIE coordinates and C.P . values of various Eu 3± doped phosphors ,[ 15 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 ] as a function of the asymmetry ratio, as shown in Table S2 (Supporting Information) and Figure 4 , including Ca 3 WO 6 :(Eu 3+ , K + ), which will provide more insight into the correlation of the C.P . value with the asymmetry ratio.…”

“…Red-color purity of Eu 3+ luminescence as a function of asymmetry ratio. The data for Ca 3-2x Eu x K x WO 6 are plotted as red diamonds (♦).YAG(Y 2.97 Al 5 O 12 :0.03Eu 3+ ),[50] (YBO)Y 0.8 BO 3 :0.2Eu 3+ ,[51] YAO(Y 0.95 AlO 3 :0.05Eu 3+ ),[52] YVO(Y 0.95 VO 4 :0.05Eu 3+ ),[53] YO(Y 1.998 O 3 :0.002 Eu 3+ ),[54] YOS(Y 1.88 O 2 S:0.12Eu 3+ ),[55] BTO(Ba 0.94 TiO 3 :0.06Eu 3+ ),[56] BZO(BaZr 0.97 O 3 :0.03Eu 3+ ),[57] SZO(Sr 0.97 ZrO 3 :0.03Eu 3+ ),[57] CYNO (Ca 2 Y 0.6 NbO 6 :0.4Eu 3+ ),[58] SWO(Sr 2.4 WO 6 :0.3(K + ,Eu 3+ )),[15] LBGMO (Li 3 Ba 2 Gd 0.6 Eu 2.4 (MoO 4 ) 8 ),[59] BBBO(Ba 3 (Bi 0.5 Eu 0.5 ) 2 (BO 3 ) 4 ),[60] YSO(Y 1.95 SiO 5 :0.05Eu 3+ ),[61] CGAO(CaGd 0.93 AlO 4 :0.07Eu 3+ ),[62] and CLPO(Ca 9.9 Li(PO 4 ) 7 :0.1Eu 3+ ) [63]. The corresponding CIE coordinates are given in TableS2(Supporting Information).…”

Phosphors Ba2LaTaO6:Mn4+ and its alkali metal charge compensation for plant growth illumination

“…A series of BLT: x Mn 4+ phosphors ( x = 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, and 0.007) was prepared via a high‐temperature solid‐state reaction. The BaCO 3 , La 2 O 3 , and Ta 2 O 5 used were the same as those published previously by our group [20]. The MnCO 3 used was also purchased directly from Shanghai Sinopharm Group with AR purity.…”