Spectroscopic properties of Dy3+ ions in LiYO2 single crystals

The Butterfly Effect: Multifaceted Consequences of Sensitizer Concentration Change in Phase Transition-based Luminescent Thermometer of LiYO2:Er3+,Yb3+

“…LiYO 2 crystallizes in two crystallographic phases: a low-temperature monoclinic phase ( P21/c space group, LT) and a high-temperature tetragonal phase ( I41/amd space group, HT) (Figure a). − The phase transition temperature significantly depends on the material’s morphology (in the case of LiYO 2 single crystal, the phase transition was found at 373 K, while for nanomaterial with an average particle size of ∼50 nm, it occurs around 293 K), and the type and concentration of dopant ions. , Regardless of the temperature, the structural transition results in a change in the size of the unit cell from a = 6.1493(8) Å, b = 6.1500(10) Å, c = 6.2494(2) Å, β = 119.091(5)° to a = 4.4468(9) Å, c = 10.372(22) Å and the point symmetry of Y 3+ ions from C 2 to D 2d . The change in the point symmetry of the Y 3+ cation is particularly significant as lanthanide dopant ions substitute for the Y 3+ cation, and the point symmetry significantly modifies the spectroscopic properties of the dopant.…”

“…Consequently, a thermally induced structural phase transition emerges as a pivotal modulator of the spectroscopic properties of the phosphor, paving the way for the development of a high-sensitivity luminescent thermometer. − This advancement is achieved through a ratiometric temperature readout, where the thermometric parameter is defined by the ratio of the integrated intensity of the bands corresponding to individual structural phases. An excellent example of such host material is LiYO 2 , undergoing a structural phase transition from a monoclinic (low-temperature phase) to a tetragonal structure (high-temperature phase) around room temperature, resulting in an alteration of the point symmetry of the Y 3+ ion from C 2 to D 2d . − Previous studies have underscored the success of this strategic approach, yielding very high relative thermal sensitivities surpassing 10% K –1 .…”