We report on a Cu(II) catalyzed process for the production of cysteine based chiral carbon dots, the process does not require any thermal treatment and the carbon dots formation is...

Tungsten disulfide (WS2) monolayers have been synthesized under ultra high vacuum (UHV) conditions on quasi-free-standing hexagonal boron nitride (h-BN) and gold deposited on Ni(111). We find that the synthesis temperature control can be used to tune the WS2 structure. As documented by in situ core level and valence band photoemission and by ex situ Raman spectroscopy, the partially disordered WS2 layer obtained at room temperature transforms to the 2H-WS2 phase at about 400°C. Low energy electron diffraction confirms the existence of van der Waals epitaxy between WS2 and h-BN and gold substrates. The measured band structure indicates that the WS2 electronic structure is not affected by the interaction with the h-BN and gold substrates

Upconverting nanoparticles (UCNPs) are well-known for their capacity to convert near-infrared light into UV/visible light, benefitting various applications where light triggering is required. At the nanoscale, loss of luminescence intensity...

Upconversion nanothermometry combines the possibility of optically sensing temperatures in very small areas, such as microfluidic channels or on microelectronic chips, with a simple detection setup in the visible spectral range and reduced heat transfer after near-infrared (NIR) excitation. We propose a ratiometric strategy based on Eu 3+ ion luminescence activated through upconversion processes. Yb 3+ ions act as a sensitizer in the NIR region (980 nm), and energy is transferred to Tm 3+ ions that in turn excite Eu 3+ ions whose luminescence is shown to be thermally sensitive. Tridoped SrF 2 :Yb 3+ ,Tm 3+ ,Eu 3+ nanoparticles (average size of 17 nm) show a relative thermal sensitivity of 1.1% K À1 at 25.0 C, in the range of the best ones reported to date for Ln 3+ -based nanothermometers based on upconversion emission. The present nanoparticle design allows us to exploit upconversion of lanthanide ions that otherwise cannot be directly excited upon NIR excitation and that may provide operational wavelengths with a highly stable read out to fill the spectral gaps currently existing in upconversion-based nanothermometry.

The room-temperature controlled crystallization of monodispersed ZnS nanoparticles (average size of 5 nm) doped with luminescent ions (such as Mn 2+ , Eu 3+ , Sm 3+ , Nd 3+ , and Yb 3+ ) was achieved via a microfluidic approach. The preparation did not require any stabilizing ligands or surfactants, minimizing potential sources of impurities. The synthesized nanomaterials were characterized from a structural (XRD and XAS at lanthanide L 3 edges), morphological (TEM), and compositional (XPS, ICP-MS) perspective, giving complementary information on the materials' features. In view of potential applications in the field of optical bioimaging, the optical emission properties of the doped nanoparticles were assessed, and samples showed strong luminescent properties while being less affected by self-quenching mechanisms. Furthermore, in vitro cytotoxicity experiments were conducted, showing no negative effects and evidencing the appeal of the synthesized materials for potential applications in the field of optical bioimaging.

No abstract

Chemical approaches, either through vapor or solution routes, are applied to the preparation of tri-doped CaF2-based films for upconversion applications.

Abstract