Eu²⁺–Eu³⁺ valence transition in double, Eu-, and Na-doped PbSe from transport, magnetic, and electronic structure studies

Eu3+/2+ co-doping system induced by adjusting Al/Y ratio in Eu doped CaYAlO4: preparation, bond energy, site preference and 5D0–7F4 transition intensity

“…The dominated 5 D 0 / 7 F 4 ($703 nm) transition emission is infrequent. Only some numerable phosphors show that they have stronger intensity of 5 28 Similarly, this phenomenon has been found in CaYAlO 4 with Eu doped. But, the stronger emission of 5 D 0 -7 F 4 disappeared when Eu 3+ and Tb 3+ were codoped into CaYAlO 4 .…”

“…2,3 The luminescence properties of different rare earth ions deliver an explicit comprehension on the internal correlations between them, which is generally determined by electronic conguration of the dopant and dynamic coupling between the dopant and the host lattices. 4,5 The local structure around the rare earth in the crystal lattice also plays an important role in controlling its luminescence performance especially the 4f-5d transitions. 6,7 Eu ions, including Eu 3+ and Eu 2+ , are the most commonly used activators in phosphor materials among the rare-earth ions.…”

“…The bond parameters of the central atom and values of bond energy when Eu 3+ locates at Ca, Y, and Al sites in CaYAlO 4 . All of the bond energy unit are kcal mol À1 Decay rates of radiative (A rad ), nonradiative (A nrad ), and total (A tot ) processes of5 D 0 -7 F J transitions, luminescence lifetime (s), intensity parameters (U 2 , U 4 ), quantum efficiencies (h) and actual quantum efficiency (h a ) of CaY 1Àx Al 1+x O 4 :2%Eu Samples A rad A nrad A tot s Open Access Article. Published on 02 July 2018.…”