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

Correction for ‘Highly efficient green up-conversion emission from fluoroindate glass nanoparticles functionalized with a biocompatible polymer’ by G. Lesly Jimenez et al., RSC Adv., 2022, 12, 20074–20079, https://doi.org/10.1039/D2RA03171J.

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

Up-conversion nanoparticles have garnered lots of attention due to their ability to transform low energy light (near-infrared) into high-energy (visible) light, enabling their potential use as remote visible light nano-transducers. However, their low efficiency restricts their full potential. To overcome this disadvantage, fluoroindate glasses (InF₃) doped at different molar concentrations of Yb³⁺ and Er³⁺ were obtained using the melting–quenching technique, reaching the highest green emission at 1.4Yb and 1.75Er (mol%), which corresponds to the ⁴S_3/2 → ⁴I_15/2 (540–552 nm) transition. The particles possess the amorphous nature of the glass and have a high thermostability, as corroborated by thermogravimetric assay. Furthermore, the spectral decay curve analysis showed efficient energy transfer as the rare-earth ions varied. This was corroborated with the absolute quantum yield (QY) obtained (85%) upon excitation at 385 nm with QYEr = 17% and QYYb = 68%. Additionally, InF₃–1.4Yb–1.75Er was milled and functionalized using poly(ethylene glycol) to impart biocompatibility, which is essential for biomedical applications. Such functionalization was verified using FTIR, TG/DSC, and XRD.

Up-conversion nanoparticles have garnered lots of attention due to their ability to transform low energy light (near-infrared) into high-energy (visible) light, enabling their potential use as remote visible light nano-transducers.

Tunable upconversion emission in NaLuF4-glass-ceramic fibers doped with Er3+ and Yb3

Novel glass-ceramic optical fibers containing NaLuF₄ nanocrystals doped with 0.5ErF₃ and 2YbF₃ (mol%) have been prepared by the rod-in-tube method and controlled crystallization. NaLuF₄ nanocrystals with a size around 20 nm are obtained after heat treatment at 600 °C. Intense upconverted green and red emissions due to (²H_11/2, ⁴S_3/2) → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 transitions, respectively, together with a blue emission due to ²H_9/2 → ⁴I_15/2 transition have been observed under excitation at 980 nm. The intensity of the green and red upconversion bands shows a nearly linear dependence on the excitation power which can be explained by saturation effects in the intermediate energy states and proves that a sensitized energy transfer upconversion process is responsible for the population of the emitting levels of Er³⁺ ions. The upconversion emission color changes from yellow to green by increasing the excitation power density which allows to manipulate the color output of the Er³⁺ emission in the glass-ceramic fibers. The tunable emission color is easily detected with the naked eye. This interesting characteristic makes these glass-ceramic fibers promising materials for photonic applications.

Novel glass-ceramic optical fibers containing NaLuF₄ nanocrystals doped with 0.5ErF₃ and 2YbF₃ (mol%) have been prepared by the rod-in-tube method and controlled crystallization.

Investigation of the aluminum oxide content on structural and optical properties of germanium glasses doped with RE ions

In this paper structural and optical properties of Rare Earth doped (RE) gallo-germanate glasses modified with various amount of Al₂O₃ have been investigated. Glasses doped with Yb³⁺, Tm^3+, and Ho³⁺ ions were synthesized to study Al₂O₃ additive influence on their structural and emission properties in the visible spectral region. MIR spectra indicated that the structure of prepared glasses tends to order and its polymerization along with the aluminum content increase. Glass samples consisting of the low molar content of Al₂O₃ are characterized by a significant contribution of Tm³⁺ ions in light emission while Ho³⁺ ions luminescence dominates in samples consisting of the higher molar content of Al₂O₃. Additionally, investigation of light emission in visible range showed that samples consisting of the low molar content of Al₂O₃ are characterized by greenish blue light emission whereas light emitted by samples consisting of 15-20 mol% is much closer to the white colour.

Analysis of upconversion luminescence in germanate glass and optical fiber codoped with Yb3+/Tb3+

In this paper, upconversion (UC) luminescence processes in a GeO₂-Ga₂O₃-BaO glass system codoped with 0.7Yb₂O₃/(0.07-0.7)Tb₂O₃ (mol.%) and double-clad optical fiber codoped with 0.7Yb₂O₃/0.7Tb₂O₃ (mol.%) were investigated. The highest emission intensity (energy transfer efficiency equals 12.92%) was obtained for 0.7Yb₂O₃/0.7Tb₂O₃ codoped glass. Comparative analysis showed significant differences in the shape of luminescence of fabricated germanate glass and optical fiber. Due to dominant transition from D₄5 sublevel the main green UC peak (Tb³⁺:  D₄5→F₅7) of fabricated double-clad optical fiber is shifted by 4 nm toward longer wavelengths.

Structural and optical study on antimony-silicate glasses doped with thulium ions

Structural, spectroscopic and thermal properties of SiO₂-Al₂O₃-Sb₂O₃-Na₂O glass system doped with 0.2 mol% Tm₂O₃ have been presented. Synthesis of antimony-silicate glasses with relatively low phonon energy (600 cm(-1), which implicates a small non-radiative decay rate) was performed by conventional high-temperature melt-quenching methods. The effect of SiO₂/Sb₂O₃ ratio in fabricated Tm(3+) doped glass on thermal, structural and luminescence properties was investigated. On the basis of structural investigations decomposition of absorption bands in the infrared FTIR region was performed, thus determining that antimony ions are the only glass-forming ions, setting up the lattice of fabricated glasses. Luminescence band at the wavelength of 1.8 μm corresponding to (3)F₄→(3)H₆ transition in thulium ions was obtained under 795 nm laser pumping. It was observed that combination of relatively low phonon energy and greater separation of optically active centers in the fabricated glasses influenced in decreasing the luminescence intensity at 1800 nm.

Analysis of thermal and structural properties of germanate glasses co-doped with Yb(3+)/Tb(3+) ions

In the work the new glass compositions in the GeO2-GaO-BaO system have been prepared and thermal, structural properties of in germanate glasses co-doped with Yb(3+)/Tb(3+)ions were studied. Glasses were obtained by conventional high-temperature melt-quenching technique. The study of the crystallization kinetics processes of glasses co-doped with 0.7Yb2O3:0.7Tb2O3 was performed with DSC measurements. The activation energies have been calculated using Freedman analysis and verified with the Flynn-Wall-Ozawa method. In this order, the DSC curves have been registered with different heating rates, between 5 and 15 degrees/min. The structure of fabricated glasses has been studied by infrared and Raman spectroscopes. The effect of heat treatment on the structural properties was determined. In all glass samples the dominated infrared absorbance band at 800cm(-1) corresponds to asymmetric stretching motions of GeO4 tetrahedra containing bridging (Ge-O(Ge)) and non-bridging (Ge-O(-)) oxygens. Additionally, the influence of heat treatment on the luminescent properties was evaluated. Strong luminescence at 489, 543, 586 and 621nm corresponding to (5)D4→(7)FJ (J=6, 5, 4, 3) transitions was measured. The highest upconversion emission intensity was obtained in the germanate glass co-doped with 0.7Yb2O3/0.7Tb2O3.