Ultraviolet upconversion emission of Pb²⁺ ions sensitized by Yb³⁺-trimers in CaF₂

Abstract

Under 978 nm near infrared (NIR) excitation, ultraviolet (UV) upconversion (UC) emissions from Pb 2+ ions in With the development of manufacturing technology for nanometer materials, UCL labelling has gathered great attention.8-11 The study on UCL was derived from the detection of IR light; however, it has a great number of potential applications in the elds of solid-state lasers, 3D displays, IR quantum counters, optical probes in uorescent imaging techniques, anti-counterfeiting, NIR photocatalysis, and temperature sensors. 6,7,9,10,[12][13][14][15] Most of UC materials are rareearth doped solid compounds; in which, a lanthanide ion absorbs more than one photon with lower energy and converts them to one photon with higher energy by using its metastable energy levels. Yb 3+ ion has been extensively adopted as a sensitizer in UC processes because it has a long excited state lifetime and a relatively large absorption cross-section in the NIR region. ion from the view of energy. Cooperative transition usually means the physical processes in which identical ions or atoms simultaneously make transitions by absorbing (or emitting) one photon with the sum of all transition energies, or transferring their energies to another ion or atom. Cooperative transition includes cooperative luminescence (CL), cooperative absorption (CA), and cooperative energy transfer (CET) and is closely relative to clustered lanthanide ions in solid hosts. Clusters made of lanthanide ions can easily form in many materials, especially in alkaline-earth uoride crystal AF 2 (A ¼ Ca, Sr, Ba). When a lanthanide ion with +3 oxidation state is doped in an alkaline-earth uoride, nonequilibrium of charge arises in the lattice due to the lanthanide ion usually occupy the position of an alkaline-earth ion with +2 oxidation state. The non-equilibrium of charge produces crystal defects such as the interstitials of F À ions and cation vacancies in order to compensate excess plus charges, which gives non-uniform distribution of lanthanide ions.

Thermally Stable Copper(II)-Doped Cesium Lead Halide Perovskite Quantum Dots with Strong Blue Emission

“…Notably, an additional PL peak of CsPb 0.77 Cu 0.23 Br 3 QDs at 430 nm can be observed in Figure 3b, which may be due to emission of Cu 2+ in the host at a high doping level. 45 Generally, the blue-shifted optical spectra can be attributed to contraction of the host perovskite, leading to a stronger interaction between Pb and Br orbitals.…”

Linear Coassembly of Upconversion and Perovskite Nanoparticles: Sensitized Upconversion Emission of Perovskites by Lanthanide‐Doped Nanoparticles

“…A plausible explanation could be that NaYF 4 :Yb 3+ ,Er 3+ /Tm 3+ NPs sensitize Pb 2+ ions after the multiphoton upconversion processes (Figure S13, Supporting Information), [ 20 ] and recycles this energy, thus eventually resulting in the sensitization of Tm 3+ /Er 3+ levels of the UC and UC CS polymers. [ 21 ]…”

“…A plausible explanation could be that NaYF 4 :Yb 3+ ,Er 3+ /Tm 3+ NPs sensitize Pb 2+ ions after the multiphoton upconversion processes ( Figure S13, Supporting Information), [20] and recycles this energy, thus eventually resulting in the sensitization of Tm 3+ /Er 3+ levels of the UC and UC CS polymers. [21] The absorption spectrum of UC Tm -CsPbBr 3 copolymer showed a peak at about 505 nm and emission peak centered at about 513 nm (λ exc = 365 nm) ( Figure S14, Supporting Information), similarly to the CsPbBr 3 NPs and CsPbBr 3 polymer, Figure S10 (Supporting Information).…”

Ultrahigh Quantum Efficiencies from Photon Multiple-Fission in Yb3+ Clusters

“…33 In the following years, we were working on the cooperation transitions in Yb 3+ clusters, and realized the energy transfer of Yb 3+ ion cluster to Cu 2+ , Pb 2+ , Sm 2+ , Eu 3+ , Tb 3+ in CaF 2 host, and found a special uorescence quenching caused by structural destruction of clusters. [34][35][36][37][38][39][40][41] In this article, an ultrahigh QE uorescent material containing Yb 3+ clusters is reported. E cient Yb 3+ uorescent clusters were found formed in CaF 2 matrix when a suitable amount of Yb 3+ ions was doped under special synthesis conditions.…”