Splitting upconversion emission and phonon‐assisted population inversion of Ba₂Y(BO₃)₂Cl:Yb³⁺, Er³⁺ phosphor

Abstract

Upconversion (UC) peak of 4 S 3/2 ? 4 I 15/2 transition of Er 3+ is close to that of 2 H 11/2 ? 4 I 15/2 transition. The UC emission splitting of Er 3+ caused by coordination fields of host results in that it is difficult to confirm which transitions ( 4 S 3/2 ? 4 I 15/2 or 2 H 11/2 ? 4 I 15/2 ) are responsible for the splitting UC emission peaks. In this work, the UC luminescence peaks located at 524, 540, 551, 565, 662, 677, and 683 nm were observed in the Ba 2 Y(BO 3 ) 2 Cl:Yb 3+ , Er 3+ phosphor upon the 980 nm excitation. The 524 and 540 nm UC emissions intensity were increased, while the 551 and 565 nm UC emissions intensity were decreased with the temperature increasing from 323 to 573 K, which is attributed to the phononassisted population inversion from the 4 S 3/2 to 2 H 11/2 level. The temperature dependence of UC emission spectra demonstrated that the 524 and 540 nm UC emissions are from 2 H 11/2 ? 4 I 15/2 transition, and 551 and 565 nm UC emissions are from the 4 S 3/2 ? 4 I 15/2 transition. Temperature sensing property was characterized by the UC intensity ratio of the 2 H 11/2 ? 4 I 15/2 transition to 4 S 3/2 ? 4 I 15/2 transition. The Ba 2 Y(BO 3 ) 2 Cl:Yb 3+ ,Er 3+ phosphor has potential application as the non-contact temperature sensor.

New Strategy for Circumventing the Limitation of Thermally Linked States and Boosting the Relative Thermal Sensitivity of Luminescence Ratiometric Thermometry

“…As is known, trivalent rare-earth ions, when embedded in a host which provides a suitable crystal field, will emit characteristic luminescence, in the form of up- or down-conversion. , Because of this unique property, they have been investigated intensively and are used widely in lots of fields. − In general, the luminescence generated from these ions is closely related with the surrounding micro- or nano-scale environment, for instance, the local summery of the crystal field. , Moreover, the changes of the luminescence are always associated with the changes of many factors. Therefore, rare-earth ions are always used for the purpose of detection by monitoring their luminescence’s variation in response to the surrounding factors. − It is worth mentioning that they have found their applications in the field of optical thermometry over the past few decades. − Especially, luminescence ratiometric thermal sensing has attracted considerable attention as it is immune to the excitation source’s fluctuations and the optics transmission losses. , …”

An upconversion luminescence and temperature sensor based on Yb3+/Er3+ co-doped GdSr2AlO5

“…The refinement finally converged to χ 2 = 1.686, R wp = 7.79% and R p = 6.29%, indicating that our prepared samples is single phase because all the observed peaks suit the reflection conditions. Furthermore, the lattice constants of GdSr 2 AlO 5 :6%Yb 3+ /1%Er 3+ are a = b = 6.70508 ( ref. 12 ) Å, c = 10.90337 ( ref.…”

Exploiting the Yb3+ and Er3+ Codoped β-NaYF4 Nanoparticles as Luminescent Thermometers for White-LED-Free Thermal Sensing at the Nanoscale

“…The UC mechanism and specific processes responsible for these four transitions are graphically depicted in Figure b . It can be seen clearly that both the 380 and 410 nm emission bands come from the three-photon UC mechanism, while the 520 and 540 nm ones, which have been sufficiently investigated, , stem from the two-photon UC mechanism.…”