Lanthanide-doped upconversion nanoparticles (UCNPs) have shown potential applications in diverse fields. However, their upconversion luminescence (UCL) intensity and excitation wavelength range are limited by the weak and narrowband absorption of lanthanide ions. Herein, we introduce and validate a strategy to largely increase the absorptivity and upconversion luminescence intensity under 808 nm excitation by broadband dye-sensitized quenching-shield sandwich structured upconversion nanocrystals NaLuF:Gd,Yb,Tm@NaLuF:Gd,Yb@NaNdF:Yb. The dye molecules anchored on the surface of the UCNPs serve as an antenna which can broadly and strongly harvest NIR light. The Nd facilitates the energy transfer and photon upconversion of the lanthanide activator at a biocompatible excitation wavelength (around 800 nm) with a significant increase in penetration ability and minimizes the overheating problem associated with conventional 980 nm excitation. The quenching-shield sandwich structure can greatly eliminate the deleterious cross-relaxation pathway between the activator and sensitizer. This approach combines the merits of the use of Nd as a sensitizer, a quenching-shield sandwich structure and the "antenna" effect, leading to a tremendous enhancement of UCL under excitation at 808 nm. These well-designed UCNPs excited at 808 nm with improved optical performances will outperform conventional UCNPs excited at 980 nm and play an important role in the development of luminescent probes for future biological and medical applications.

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The aim of this study was to investigate the feasibility of utilizing the fruiting bodies of a jelly macro-fungus Auricularia polytricha as adsorbents to remove emulsified oil from water. The effects of several factors, including temperature, initial pH, agitation speed, and adsorbent dosage, were taken into account. Results showed that the optimized conditions for adsorption of A. polytricha were a temperature of 35°C, pH of 7.5, and agitation speed of 100 rpm. The adsorption kinetics were characterized by the pseudo-first order model, which showed the adsorption to be a fast physical process. The Langmuir-Freundlich isotherm described the adsorption very well and predicted the maximum adsorption capacity of 398 mg g−1, under optimized conditions. As illustrated by scanning electron micrographs, the oil particles were adsorbed onto the hairs covering the bottom surface and could be desorbed by normal temperature volatilization. The material could be used as an emulsified oil adsorbent at least three times, retaining more than 95% of the maximum adsorption capacity. The results demonstrated that the fruiting bodies of A. polytricha can be a useful adsorbent to remove emulsified oil from water.

In this work, Er/Al/Ge co-doped silica glasses with different GeO2 content (0–3 mol%), as well as Ge/Al co-doped silica glasses, are prepared by combining the sol–gel and high-temperature sintering methods. Further, the effects of the GeO2 content on the absorptions and emissions properties, and lifetimes of the glasses before and after 1KGy γ-ray irradiation are compared. The Er/Al/Ge co-doped silica fibers are prepared from a preform produced via modified chemical vapor deposition (MCVD) combined with nano sol-doping. The effects of Ge co-doping on the optical loss and amplifier gain of the Er-doped silica fibers (EDFs) before and after irradiation are also investigated. The related mechanism and species of the γ-ray radiation-induced color centers are revealed via radiation-induced-absorption (RIA) and continuous wave electron paramagnetic resonance (CW-EPR) spectroscopies. The results revealed that co-doping with GeO2 considerably improves the radiation resistance of the glass and exerts a slight effect on the spectral properties of the Er/Al/Ge co-doped silica glasses before irradiation. The RIA and CW-EPR spectra revealed that the aluminum–oxygen hole center (AlOHC) defects reduce with increasing GeO2 content because the intermediaries, the Ge-related oxygen-deficient centers (GeODC(I) and GeODC(II)), exhibit stronger abilities to trap the holes compared with the [AlO4/2]− group. This reduces the RIA level in the visible and near-infrared regions of the Er/Al/Ge co-doped silica glass. The irradiation experiment on the fiber further confirmed that the radiation resistance of EDFs can be considerably improved by Ge co-doping.