Unusual behavior of Tb^3+ in K_3YF_6 green-emitting phosphor

Abstract

We report on photoluminescence studies of Tb3+ in a polycrystalline cryolite type K3YF6 host. The location of the Tb3+ in the center of inversion forbids the electric-dipole transitions of terbium ions in this material. As a consequence almost the entire luminescence intensity is related to the 5D4-(7)F5 magnetic-dipole transition, and it is contained in the extremely narrow spectral bandwidth amounting to 1.7 nm at 8K and to 18 nm at room temperature. The phosphor under study can be efficiently excited making use of intense f-d transitions of Tb3+ in the UV-vacuum-UV region and may be of interest for applications requiring high spectral purity of the emission.

Influence of Matrix on the Luminescent and Structural Properties of Glycerine-Capped, Tb3+-Doped Fluoride Nanocrystals

“…45 However, a different situation could also occur as the result of interactions between high-spin 5d and excited 4f 8 levels. 46 In the registered excitation spectra of LaF 3 :Tb 3+ , the 7 F J → 9 D J transition (∼283 nm) has a larger intensity than the 7 F J → 7 D J (∼247 nm) transition. There are also visible 4f 8 →4f 8 transition bands displayed in Figure 5a.…”

Concentration-dependent luminescence of Tb3+ ions in high calcium aluminosilicate glasses

“…It could be noticed from this figure that at the lower concentrations of Tb 3+ up to 2 wt%, the intensity of peak at 244 nm representing 7 D j spin allowed transitions has been found to be more compared to the intensity of 9 D j spin forbidden multiplet transitions at 284 nm but this relative intensity has been reversed with the increase of terbium concentration beyond 2 wt% in glass samples. This behaviour of excitation band intensities implies an important interaction between the high-spin 5d levels and the excited energy levels of 4f 8 configuration of Tb 3+ ions [31], which will be discussed later. The second part of the excitation spectra of Tb 3+ calcium aluminosilicate glasses has demonstrated two intense peaks of f-f transitions, (i) a broad band centred at 374 nm and it is attributed to superimposition of transitions 7 F 6 -( 5 D 3 , 5 G 6 ), 5 L 10 , ( 5 L 9 , 5 G 4 ), ( 5 G 2 , 5 L 6 ) and ( 5 H 7 , 5 D 0 , 1 ), respectively, [24,25] and (ii) at 482 nm is assigned to transition 7 F 6 -5 D 4 .…”

Time-resolved luminescent biosensing based on inorganic lanthanide-doped nanoprobes

“…93 On the other hand, it is feasible to realize single-band PL from Ln 3+ with high spectral purity in host matrices with peculiar crystal structures. [101][102][103][104][105] Unusual single-band emission from Tb 3+ at B545 nm was discovered in cryolite-type K 3 YF 6 bulk phosphors. 101 The local site symmetry of Tb 3+ in the centre of inversion forbids the electricdipole transitions of Tb 3+ ions in this material.…”

“…[101][102][103][104][105] Unusual single-band emission from Tb 3+ at B545 nm was discovered in cryolite-type K 3 YF 6 bulk phosphors. 101 The local site symmetry of Tb 3+ in the centre of inversion forbids the electricdipole transitions of Tb 3+ ions in this material. As a result, almost the entire PL intensity is related to the magnetic-dipole transition of 5 D 4 -7 F 5 with extremely narrow FWHM down to 1.7 nm.…”