Decay times of the spin-forbidden and spin-enabled transitions of Yb²⁺ doped in CsCaX₃ and CsSrX₃ (X = Cl, Br, I)

Abstract

In this paper, a systematic study of the decay times of the spin-enabled and spin-forbidden transitions of Yb doped into the halidoperovskites CsMX (M = Ca, Sr; X = Cl, Br, I) is presented. The spin-forbidden transitions are characterized by ms decay times, which are typical for Yb. On the contrary, the spin-enabled transitions show much shorter decay times in the range of μs and have so far only been rarely observed. These results allow detailed conclusions about systematics of the decay times of Yb doped in similar compounds and their correlation to the local structure of the coordination sphere of Yb as well as the role of vibrational interaction between the excited high spin (HS) and low spin (LS) states. The halidoperovskites are ideally suited as host lattices in this context and may work as text book examples due to their comparable structures, which allows a detailed interpretation of the decay times in relation to the local structure. An understanding of the impact of the composition and structure of the host material on the decay times of Yb will be of relevance for future applications of this activator in scintillators or lighting materials.

Luminescence of BaBrI and SrBrI single crystals doped with Eu2+

“…Following the diagram we can expect the bright luminescence 5d-4f from Sm 2+ and Yb 2+ ions in SrBrI crystals. It would be promising for creation the fast scintillators [29,30]. The Ce-doping is also prospecting way due to 5d state of Ce 3+ ion could be located in sufficiently far from the bottom of conduction band to avoid quenching.…”

A Theoretical Framework for Ratiometric Single Ion Luminescent Thermometers—Thermodynamic and Kinetic Guidelines for Optimized Performance

“…[118,179,180] For the sake of completion, it is also noteworthy that divalent lanthanides such as Sm 2+ , [181][182][183] Eu 2+ , [184] Tm 2+ [185][186][187][188] and especially Yb 2+ [189][190][191][192] show potential for luminescence thermometry, although their thermal behavior is often not governed by simple Boltzmann statistics anymore, but more complex temperaturedependent excited state dynamics involving a crossover to the 4f n-1 5d 1 configuration. [193,194] Unlike the chemically more challenging examples of divalent lanthanides, Pr 3+ has also recently been introduced as an alternative, more stable luminescent thermometer with the same underlying principle of a 4f 2 -4f 1 5d 1 crossover (with eventual incorporation of thermal ionization into the conduction band). [195][196][197] The presented overview is still by no means complete and demonstrates the extremely rapid evolution of the research field.…”

Investigations on electron beam irradiated rare-earth doped SrF2 for application as low fading dosimeter material: evidence for and DFT simulation of a radiation-induced phase

“…Both emissions are only barely observed in unirradiated powders. Based on literature data, 24–26 we assign the peak at 421 nm to the regular emission 4f 13 5d → 4f 14 of Yb 2+ . The literature data on the spectral position of this emission ranges from 412 nm 25 to 447 nm.…”

“…The literature data on the spectral position of this emission ranges from 412 nm 25 to 447 nm. 26 Differences can be attributed to the varying crystal field in different host lattices and its effect on the excited d-levels of Yb 2+ . The second, broader emission band can be attributed to the inter valence charge transfer (IVCT) emission of Yb in SrF 2 which is described as the transition Yb 2+ [ 2 F 5/2 E g (5d)– 2 A 1u ] + Yb 3+ –> Yb 3+ [ 2 F 7/2 –G 7u ] + Yb 2+ [4f 14 –A 1g ] at 521 nm.…”