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Despite the excellent thermometric performance of many developed luminescent nanomaterials, their use has not gone beyond proof‐of‐concept in vivo experiments to date. An important issue that needs to be resolved before moving toward true biomedical applications of engineered nanothermometers is their potential toxicity and bioaccumulation in the human body considering the ultimate objective of clinical applications. Since most reported nanothermometers currently are not degradable materials and are mainly based on the incorporation of heavy metal ions, these aspects remain of genuine concern in the fields of nanomedicine, nanobiotechnology, nanotoxicology, and nanopharmacology. This work explores the possibility of designing visible, as well as near‐infrared, emitting luminescent ratiometric nanothermometers based on appropriate organic dye mixtures embedded in hollow disulfide‐bridged periodic mesoporous organosilica (PMO) particles. Such hybrid particles show excellent thermometric performance in the physiological temperature range (20–50 °C), favorable degradability in simulated physiological conditions, as well as no toxicity to healthy normal human dermal fibroblast (NHDF) cells in a wide concentration range. Considering the simplicity of the approach from the synthetic point of view, and the large available library of known fluorescent dyes emitting in various regions of the electromagnetic range, this motif renders a very promising approach to designing novel non‐toxic, decomposable, luminescent ratiometric thermometers. [ABSTRACT FROM AUTHOR]

The most efficient upconversion (UC) materials reported to date are based on fluoride hosts with low phonon energies, which reduce the amount of nonradiative transitions. In particular, NaYF4 doped with Yb3+ and Er3+ at appropriate ratios is known as one of the most efficient UC phosphors. However, its low thermal stability limits its use for certain applications. On the other hand, oxide hosts exhibit better thermal stability, yet they have higher phonon energies and are thus prone to lower UC efficiencies. As a result, developing host nanomaterials that combine the robustness of oxides with the high upconversion efficiencies of fluorides remains an intriguing prospect. Herein, we demonstrate the formation of ytrrium doped oxyfluoride (YOF:Yb3+,Er3+) particles, which are prepared by growing a NaYF4:Yb3+,Er3+ layer around SiO2 spherical particles and consecutively applying a high-temperature annealing step followed by the removal of SiO2 template. Our interest lies in employing these materials as Boltzmann type physiological range luminescence thermometers, but their weak green emission is a drawback. To overcome this issue, and engineer materials suitable for Boltzmann type thermometry, we have studied the effect of introducing different metal ion co-dopants (Gd3+, Li+ or Mn2+) into the YOF:Yb3+,Er3+ particles, focusing on the overall emission intensity, as well as the green to red ratio, upon 975 nm laser excitation. These materials are explored for their use as ratiometric thermometers, and further also as drug carriers, including their simultaneous use for these two applications. The investigation also includes examining their level of toxicity towards specific human cells – normal human dermal fibroblasts (NHDFs) – to evaluate their potential use for biological applications. [ABSTRACT FROM AUTHOR]

25 years after the first papers on the development of Periodic Mesoporous Organosilicas, and in this special issue in honor of prof. Ozin who stood at the cradle of PMOs, we here report for the first time an "acac-PMO" with the acac-functionality intact and embedded in the organic environment of the linker. Periodic mesoporous organosilicas (PMOs) have emerged as versatile sensors due to their stability, low toxicity, and scalability. This study reports for the first time on embedding the acetylacetone (acac) group into the PMO backbone. This integration of acac into the PMO framework opens new applications in both sensing and catalysis. The Eu3+ grafted acac-PMOs demonstrate enhanced sensitivity, with a detection limit of 108 nM, and high selectivity in aqueous copper (Cu2+) ion sensing. Additionally, these novel PMOs show high catalytic efficiency in Mannich reactions. [ABSTRACT FROM AUTHOR]

This study explores the potential of combining periodic mesoporous organosilicas (PMOs) with a fluorescent dye to develop a ratiometric thermometry system with enhanced stability, sensitivity, and biocompatibility. PMOs, ordered porous materials known for their stability and versatility, serve as an ideal platform. Curcumin, a natural polyphenol and fluorescent dye, is incorporated into PMOs to develop curcumin-functionalized PMOs (C-PMO) and curcumin-pyrazole-functionalized PMOs (CP-PMO) via hydrolysis and co-condensation. These PMOs exhibit temperature-dependent fluorescence properties. The next step involves encapsulating rhodamine B (RhB) dye within the PMO pores to create dual-emitting PMO@dye nanocomposites, followed by a lipid bilayer (LB) coating to enhance biocompatibility and dye retention. Remarkably, within the physiological temperature range, C-PMO@RhB@LB and CP-PMO@RhB@LB demonstrate noteworthy maximum relative sensitivity (Sr) values of up to 1.69 and 2.60% K−1, respectively. This approach offers versatile means to create various ratiometric thermometers by incorporating different fluorescent dyes, holding promise for future temperature sensing applications. [ABSTRACT FROM AUTHOR]

Recent research in lanthanide materials has strongly contributed to the development of high-performance chemical sensors. However, the current reported high-responsive chemical sensors still have a limited detection range, restraining their further application. We developed lanthanide-based periodic mesoporous organosilica (LnPMO) hollow spheres with interior lanthanide-doped fluorides for luminescence turn-off sensing of Hg2+ with a low detection limit and wide detection range. This yolk–shell structure was built of Tb3+ grafted diureido-benzoicacid PMO (shell) and lanthanide-doped fluoride NaYF4:Yb,Er (yolk), exhibiting both downshifting (DS) and upconversion (UC) luminescence. Visible photoluminescence properties of the developed hybrid material were studied using UV and near-infrared (NIR) excitation. In DS mode, benzoic acid-functionalized PMO acts as an organic co-sensitizer for Tb3+ β-diketonate complexes, which can significantly enhance the ion sensing and detection range. In UC mode, Hg2+-responsive rhodamine B thiolactone (RBT) was used as an antenna species for the lanthanide-doped fluorides to sense Hg2+ with high sensitivity. [ABSTRACT FROM AUTHOR]

Developing core–shell nanoparticles is a common approach to improve the luminescence performance of nanomaterials, as an inert shell shields the core, which is doped with luminescent ions, from the quenching influence of the environment. Core-only nanoparticles are susceptible to solvent overtones, which can couple with the emissive dopants on the surface and quench their intensity. This is undeniably highly undesired for any luminescence application. It was recently shown by some of us that previously unreported ion migration takes place in 2%Er,18%Yb:LiLuF4@LiLuF4 core–shell nanoparticles, which was proven both with energy-dispersive X-ray (EDX) maps and high-temperature luminescence measurements. These findings lead us to the investigation presented here, which explores in detail how to hinder the migration of Er3+ and Yb3+ ions in LiLuF4 and LiYF4 hosts by implementing an interface region. First, different synthesis routes were explored to see if the chosen approach had any effect on the ion migration process from the doped core into the inert shell in a homogeneous core–shell system. Next, a LiYF4 inert shell was grown around a 2%Er,18%Yb:LiLuF4 core forming a heterogeneous core–shell system. We observed that the heterogeneous 2%Er,18%Yb:LiLuF4@LiYF4 and LiLuF4@2%Er,18%Yb:LiYF4 core–shell combinations showed significantly less ion migration based on EDX maps and high-temperature luminescence measurements exhibiting a behavior similar to the well-studied 2%Er,18%Yb:NaYF4@NaYF4 core–shell structures that, according to previous studies, show no or very little ion migration. [ABSTRACT FROM AUTHOR]

Here, three unique organic–inorganic hybrid nanocomposite materials prepared by combining NaYF4:Yb3+,Ln3+ (Ln3+ = Er3+, Tm3+, Ho3+) and periodic mesoporous organosilica (PMO) are proposed for both metal ion sensing and solvent sensing. The luminescence properties of the developed hybrid materials, PMO@NaYF4:Yb3+,Ln3+, were studied in detail in the solid state and after dispersing in water. It is found that PMO@NaYF4:Yb3+,Er3+ showed selective "turn on" luminescence for Hg2+ with the detection limit of 24.4 μM in an aqueous solution. Additionally, the above three materials showed different luminescence emission responses towards water and organic solvents. It is worth noting that all three PMO@NaYF4:Yb3+,Ln3+ materials showed "turn on" luminescence towards alcohols. PMO@NaYF4:Yb3+,Er3+ and PMO@NaYF4:Yb3+,Ho3+ were selected and further developed into sensitive sensors for the detection of water in alcohols by taking advantage of their quenching behavior in water. The detection limit for sensing of water was determined to be 0.21%, 0.18% and 0.29%, corresponding to isopropanol (PMO@NaYF4:Yb3+,Er3+), n-butanol (PMO@NaYF4:Yb3+,Er3+) and ethanol (PMO@NaYF4:Yb3+,Ho3+), respectively. The above results illustrate the potential of these hybrid materials for applications in environmental fields as well as in chemical industries. [ABSTRACT FROM AUTHOR]