Simultaneous Measurement of the Emission Quantum Yield and Local Temperature: The Illustrative Example of SrF₂:Yb³⁺/Er³⁺ Single Crystals

Abstract

The emission quantum yield is one of the key figures of merit to evaluate the photoluminescence performance of luminescent materials. The emission quantum yield of upconverting materials is still not widely reported due to technical difficulties and intricate dependence on the excitation power density that is mirrored in a temperature increase. This work describes the simultaneous determination of the emission quantum yield (for both downshifting and upconverting processes) and of the temperature by using the output of a commercial integrating sphere. The temperature is calculated by primary luminescence thermometry through the Boltzmann equation, analyzing the intensity ratio between the 2H11/2, 4S3/2→4I15/2 transitions. The procedure is illustrated using of SrF2: Yb3+/Er3+ single crystals with distinct Yb3+ compositions and the effect of the Yb3+ content on the emission quantum yield and the temperature increase of the sample.

Study of stability of luminescence intensity of b-NaGdF4:Yb:Er nanoparticle colloids in aqueous solution

“…Up-conversion luminescence is convenient for bioimaging, since it allows the excitation of the phosphor in the near-infrared region of the spectrum and the registration of the luminescence response in the visible range of the spectrum [13,14]. Various techniques have been developed which allow in vivo determination of temperature [15][16][17][18], pH, and a viscosity [19] inside cells based on up-conversion nanoparticles. The highest quantum yields of up-conversion luminescence (PLQY) were recorded for β-NaYF 4 :21.4%Yb 3+ , 2.2%Er 3+ (PLQY=10.5% at 35 W/cm 2 ) [20], BaY 2 ZnO 5 :7%Yb 3+ , 3%Er 3+ (PLQY=5% at 2.2 W/cm 2 ) [21], La 2 O 2 S:9%Yb 3+ , 1%Er 3+ (PLQY=5,8% at 13 W/cm 2 ) [22], SrF 2 :3%Yb, 2%Er (PLQY=6.5% at 230 W/cm 2 ) [11].…”

Laser damage threshold of hydrophobic up-conversion carboxylated nanocellulose/SrF2:Ho composite films functionalized with 3-aminopropyltriethoxysilane

“…Rare earth-based up-conversion luminophores, that efficiently transform near-infrared irradiation to visible light (Auzel 2004;Dong et al 2013;Ovsyankin and Feofilov 1966;Qin et al 2017;Reig et al 2020), can be utilized for object visualization, biomarkers, luminescent tagging, solar elements, electronic displays, etc. (Brites et al 2020;Fischer et al 2018;Liang et al 2019;Zhou et al 2015); this includes two-micron laser irradiation visualizers, based on holmium luminescent transitions, implemented in medical equipment and lidars (Belyaev et al 2016;Lyapin et al 2017;Scholle et al 2010;Verber et al 1971). Metal fluorides are conside red most effective luminophore matrices because of low phonon energies and high probabilities of the anti-Stokes transitions allowing visualization of IR-irradiation (Fedorov et al 2011).…”

“…Laser damage threshold (Wood 2014) and thermal stability (Delone 1993) are important criteria of nanocomposite film stability and their applicability as IR-irradiation visualizers. Earlier, we have developed flexible semitransparent CNC and CNC/CNF composite films with upconversion SrF 2 :Но particles (Fedorov et al 2019) and hydrophobic TOCNF-based alkyl ketene dimer (AKD) modified composite films with up-conversion MF 2 :Ho (M = Ca, Sr) particles (Fedorov et al 2020). These composites demonstrated intense red luminescence under Ho 3+ excitation with 1912 nm laser irradiation.…”

Growth and physical properties of CaSrBaF6 single crystals

“…Фториды кальция, стронция и бария кристаллизуются в структуре типа флюорита с параметрами кристаллической решетки -5.463, 5.800 и 6.200 Å соответственно. Монокристаллы дифторидов щелочноземельных металлов широко применяются в качестве материалов фотоники [1][2][3], в том числе как матрицы для легирования редкоземельными ионами [4][5][6][7][8][9][10]. Они характеризуются широкими областями пропускания от вакуумного ультрафиолета до среднего ИК-диапазона.…”