Upconversion processes inEr3+-dopedKPb2

Abstract

In this work we report infrared to visible upconversion luminescence in the low phonon-energy host material KPb 2 Cl 5 doped with Er 3ϩ ions under 4 I 9/2 excitation. The upconversion mechanisms are investigated by using steady-state and time-resolved laser spectroscopy. When the excitation wavelength is resonant with the 4 I 9/2 level (Ϸ800 nm), the upconverted emission originates from the levels 2 H 9/2 and 4 S 3/2 . These upconverted emissions occur via energy-transfer upconversion processes. However, under nonresonant excitation at lower energies than 4 I 9/2 , the main emission results from the level 2 H 9/2 . This latter upconverted emission can be attributed to excited-state absorption of the pump radiation. The proposed upconversion mechanisms responsible for the different emissions from the levels 2 H 9/2 and 4 S 3/2 are supported by both the time evolution of the upconversion luminescence after pulsed infrared excitation and the upconversion luminescence excitation spectra. Rate equation analysis has been used to identify and characterize the energy-transfer processes responsible for the observed fluorescence behavior.

Visible upconversion luminescence of Tb3+ ions in Y2O3 nanoparticles induced by a near-infrared femtosecond laser

“…As far as upconversion luminescence is concerned, relationship between upconversion luminescence intensity and pump power density is as follows [30]:…”

Identification on Mantle Cell Lymphoma Using CD20 and CD5 Coupled Upconversion Fluorescent Nanoprobes

“…The detailed characterization processes are shown in the supplemental data I. . According to the literature [51], their dependences of the integrated upconversion luminescence intensities on laser pump powers in Figure S4 indicate that purple and blue fluorescence at 361 and 477 nm from Tm 3+ ions are four-and three-photon processes; green and red upconversion fluorescence at 540 and 657 nm from Er 3+ ions are two-photon upconversion process, respectively. The upconversion mechanisms of sample 1 and 2 are shown in Figure S5 and explained in supplemental data III.…”

Analysis of spectra of neat and lanthanide ion‐doped KPb2Cl5 excited by synchrotron radiation

“…Moreover, the occurrence of a Jahn-Teller effect cannot be envisaged in systems such as KPb 2 Cl 5 , where the static site symmetry of Pb 2þ is C 1 . The low-phonon host KPb 2 Cl 5 has attracted much attention due to its superior moisture resistance and ease of incorporation of lanthanide ions to give up- [16][17][18] or down- [19] conversion properties, infrared lasing [20][21][22][23] and antiStokes laser cooling [24,25]. The focus of many previous studies has therefore rested upon the characterization of lanthanide ion energy levels and spectral intensities in this host lattice and the site symmetries of the dopant ions [26][27][28][29].…”