Siloxane-Encapsulated Upconversion Nanoparticle Hybrid Composite with Highly Stable Photoluminescence against Heat and Moisture

Abstract

Herein, we report a siloxane-encapsulated upconversion nanoparticle hybrid composite (SE-UCNP), which exhibits excellent photoluminescence (PL) stability for over 40 days even at an elevated temperature, in high humidity, and in harsh chemicals. The SE-UCNP is synthesized through UV-induced free-radical polymerization of a sol–gel-derived UCNP-containing oligosiloxane resin (UCNP-oligosiloxane). The siloxane matrix with a random network structure by Si–O–Si bonds successfully encapsulates the UCNPs with chemical linkages between the siloxane matrix and organic ligands on UCNPs. This encapsulation results in surface passivation retaining the intrinsic fluorescent properties of UCNPs under severe conditions (e.g., 85 °C/85% relative humidity) and a wide range of pH (from 1 to 14). As an application example, we fabricate a two-color binary microbarcode based on SE-UCNP via a low-cost transfer printing process. Under near-infrared irradiation, the binary sequences in our barcode are readable enough to identify objects using a mobile phone camera. The hybridization of UCNPs with a siloxane matrix provides the capacity for highly stable UCNP-based applications in real environments.

Siloxane Hybrid Material-Encapsulated Highly Robust Flexible μLEDs for Biocompatible Lighting Applications

“…Figure b shows the Fourier-transform infrared (FT-IR) spectra of the AlInGaP-based f-HμLED during the HAST tests, showing the chemical structure changes of the SHM. The SHM maintained its primitive siloxane network for 2 weeks without any noticeable moisture absorption, showing imperceptible peak changes of Si–O–Si bond stretching (wavenumber of 1100–1000 cm –1 in the left graph) and–OH bond stretching (wavenumber of 3700–3150 cm –1 in the right graph) in the FT-IR spectrum. ,, According to these results, the f-HμLED has significant potential for long-term daily applications due to its outstanding environmental stabilities.…”

Sunlight-Driven Self-Cleaning Ultrafine Particulate Matter Filter with Antibacterial Activity

“…Further, visual confirmation of the up-converting feature of UCNP@α-Fe 2 O 3 could be verified by the emission of green light under the NIR laser irradiation onto UCNP@α-Fe 2 O 3 aqueous dispersion (Figure 2f, right inset). 30 A nonwoven membrane manufactured from borosilicate fiber glass was used as a standard PM 2.5 filter (BF) in this work. The functionalization of BF with rGO (GF) and the subsequent production of UCNP@α-Fe 2 O 3 @GF (NF) were carried out by simple vacuum filtration (details in the Experimental Section).…”

“…Green-light-emitting NaYF 4 :Yb, Er UCNPs were synthesized by a coprecipitation method. 30 Initially, YCl 3 (0.8 mmol), YbCl 3 (0.18 mmol), and ErCl 3 (0.02 mmol) were dissolved in methanol and added to a blend of oleic acid (6 mL) and 1-octadecene (15 mL). The resulting solution was vigorously stirred at 150 °C under an argon atmosphere for 15−20 min until it turned a yellowish transparent color, followed by cooling to 50 °C.…”

The development of rare-earth combined Fe-based magnetic nanocomposites for use in biological theranostics

“…Multiphase composite nanostructures based on the combination of rare-earth nanomaterials and Fe-based nanoparticles can provide alternatives with outstanding performance for biomedical purpose by incorporating the properties of rare-earth elements, such as fluorescence imaging in the NIR-II region, which enables the visualization of deep tissues 45 into magnetic materials with a union of their intrinsic magnetism. 46 Conventional methods for the synthesis of rare-earth-doped upconversion nanoparticles (UCNPs) include co-precipitation, 47 solvo/hydrothermal, 48 thermal decomposition 49 and sol–gel 50 methods, which are also the main approaches for the regulation of Fe-based nanoparticles MFe 2 O 4 (M = Fe, Co, Ni, Mn, or Zn). 4,10,46 Similar manufacturing processes can prevent material damage or denaturation caused by disparate reaction conditions like temperature, pressure and the pH value.…”