Mechanisms of Upconversion Luminescence of Er3+-Doped NaYF4 via 980 and 1530 nm Excitation

Abstract

To date, the mechanisms of Er3+ upconversion luminescence via 980 and 1530 nm excitation have been extensively investigated; however, based on discussions, they either suffer from the lack of convincing evidence or require elaborated and time-consuming numerical simulations. In this work, the steady-state and time-resolved upconversion luminescence data of Er3+-doped NaYF4 were measured; we therefore investigated the upconversion mechanisms of Er3+ on the basis of the spectroscopic observations and the simplified rate equation modeling. This work provides a relatively simple strategy to reveal the UCL mechanisms of Er3+ upon excitation with various wavelengths, which may also be used in other lanthanide ion-doped systems.

Highly efficient green up-conversion emission from fluoroindate glass nanoparticles functionalized with a biocompatible polymer

“…Host matrices with low phonon energy (e.g., NaYF 4 -350 cm À1 , ZBLAN -330 cm À1 , chalcogenide glasses -300 cm À1 , uoroindate glasses -510 cm À1 ) have been found to enhance the up-conversion emission process because of the suppression of non-radiative losses. [12][13][14][15] Among the host matrices explored, NaYF 4 is considered one of the most efficient systems; however, the high levels of OH À defects on it accelerate the quenching effect while high dopant concentrations (lanthanide ions) trigger the depletion of the excitation energy levels owing to the migration of the ions to the surface. 16,17 However, the advantage of uoroindate glasses over other low phonon energy materials is their better thermal stability, superior mechanical properties, excellent chemical resistance, and high rare-earth ion solubility.…”

Site occupation and upconversion process enabled multicolor emission in a Gd3GaO6:Bi3+,Er3+ phosphor for quad-mode anti-counterfeiting

“…These bands are assigned to the 2 H 11/2 → 4 I 15/2 (535 nm), 4 S 3/2 → 4 I 15/2 (549 nm) and 4 F 9/2 → 4 I 15/2 (645-695 nm) transitions of the Er 3+ ions, respectively. 41,42 The corresponding UC luminescence mechanisms are demonstrated in Fig. 5.…”

Simultaneous realization of FIR-based multimode optical thermometry and photonic molecular logic gates in Er3+ and Yb3+ co-doped SrTiO3 phosphor

“…According to this model, the rate equations describing the whole UC process can be represented by the following equations [50][51][52]: ' Where N i (I = 1 to 6), σ i→j , ρ P , A ij , and W ij represents the population of dopant ions in various energy levels, absorption cross section for various transitions, laser pump power, radiative, and non-radiative transition probabilities, respectively. B 31 , E 13 , U 16 , represents the coefficient of back energy transfer, energy transfer from excited state to ground state of Er 3+ and energy transfer involved in up conversion process.…”