Energy transfer between europium and manganese close pairs in monocrystalline sodium bromide

Eu2+–Mn2+ energy transfer in white-light-emitting T-phase (Ba,Ca)2SiO4:Eu2+, Mn2+ phosphor

“…5. Similar phenomena were observed in other Eu 2 + /Mn 2 + -codoped phosphors and were attributed to Eu 2 + /Mn 2 + close paring [7,[14][15][16][17]. Here, we suggest the simple reason for this interesting observation is the local inhomogeneous distribution of Eu 2 + ions around Mn 2 + sites which can give rise to the perturbation of these sites and thus violation of the Mn 2 + selection rules and enhance the Mn 2 + red emission.…”

Optical and EPR study of precipitated phases in NaBr:Mn2+

“…Moreover, they also indicate that such a line does not disappear even after heating the crystal at 800 K for several hours. Despite the similarity with some of the results reported here, Rubio et al [24] have not identified any EPR line with AH,, --3 17 G in their samples.…”

“…It is worth pointing out here that Rubio eta1 [24], working with NaBr crystals doped with 130 ppm of Mn2+ and 8 ppm of Eu2+, also detect an EPR line with Lorentzian shape and having AH,,, = 300 I 30 G at room temperature. Moreover, they also indicate that such a line does not disappear even after heating the crystal at 800 K for several hours.…”

“…Although to our knowledge no research on as-grown NaBr : Mn2+ by means of EPR and optical techniques has been carried out to date, some results on NaBr doped with Mn2+ and Eu2+ have recently been reported [24]. Such data will be compared to the present ones where no sensitiser has been introduced for detecting Mn2+ luminescence,…”

White-Emitting Phosphor Ca[sub 2]BO[sub 3]Cl:Ce[sup 3+], Eu[sup 2+] for UV Light-Emitting Diodes

“…3b shows the schematic of the energy level system, which describes the energy transfer from Ce 3+ to Eu 2+ . According to previous results, 11,17,18 the electric dipole-dipole interaction usually predominates in the ET Ce→Eu mechanism, and the critical distance ͑R c ͒ of energy transfer from a sensitizer to an activator can be expressed by [17][18][19][20][21] R c 6 = 0.63 ϫ 10 28 4.8 ϫ 10 −16 P A E 4…”