Advances in the photon avalanche luminescence of inorganic lanthanide-doped nanomaterials.

Photon avalanche (PA)-where the absorption of a single photon initiates a 'chain reaction' of additional absorption and energy transfer events within a material-is a highly nonlinear optical process that results in upconverted light emission with an exceptionally steep dependence on the illumination intensity. Over 40 years following the first demonstration of photon avalanche emission in lanthanide-doped bulk crystals, PA emission has been achieved in nanometer-scale colloidal particles. The scaling of PA to nanomaterials has resulted in significant and rapid advances, such as luminescence imaging beyond the diffraction limit of light, optical thermometry and force sensing with (sub)micron spatial resolution, and all-optical data storage and processing.

The mechanisms behind the extreme susceptibility of photon avalanche emission to quenching.

The photon avalanche (PA) process that emerges in lanthanide-doped crystals yields a threshold and highly nonlinear (of the power law order >5) optical response to photoexcitation. PA emission is the outcome of the excited-state absorption combined with a cross-relaxation process, which creates positive and efficient energy looping. In consequence, this combination of processes should be highly susceptible to small perturbations in energy distribution and can thus be hindered by other competitive "parasitic" processes such as energy transfer (ET) to quenching sites.

All-Optical Data Processing with Photon-Avalanching Nanocrystalline Photonic Synapse.

Data processing and storage in electronic devices are typically performed as a sequence of elementary binary operations. Alternative approaches, such as neuromorphic or reservoir computing, are rapidly gaining interest where data processing is relatively slow, but can be performed in a more comprehensive way or massively in parallel, like in neuronal circuits. Here, time-domain all-optical information processing capabilities of photon-avalanching (PA) nanoparticles at room temperature are discovered.

On the role of Gdions in enhancement of UV emission from Yb-Tmup-converting LiYFnanocrystals.

Materials capable of emitting ultraviolet (UV) radiation are sought for applications ranging from theranostics or photodynamic therapy to specific photocatalysis. The nanometer size of these materials, as well as excitation with near-infrared (NIR) light, is essential for many applications. Tetragonal tetrafluoride LiY(Gd)Fnanocrystalline host for up-converting Tm-Ybactivator-sensitizer pair is a promising candidate to achieve UV-vis up-converted radiation under NIR excitation, important for numerous photo-chemical and bio-medical applications.

Quantitative Comparison of the Light-to-Heat Conversion Efficiency in Nanomaterials Suitable for Photothermal Therapy.

Functional colloidal nanoparticles capable of converting between various energy types are finding an increasing number of applications. One of the relevant examples concerns light-to-heat-converting colloidal nanoparticles that may be useful for localized photothermal therapy of cancers. Unfortunately, quantitative comparison and ranking of nanoheaters are not straightforward as materials of different compositions and structures have different photophysical and chemical properties and may interact differently with the biological environment.

[Terminology concerning intravenous ports].

Ports are more and more often applied with patients requiring the permanent intravenous access, not only in the cancer treatment. Very devices, as well as procedures associated with applying them are determined in the heterogeneous way. Therefore during the last conference "Intravenous Port--implantation, care, complications" an attempt to systematize the applied terminology was made.

The impact of shell host (NaYF₄/CaF₂) and shell deposition methods on the up-conversion enhancement in Tb³⁺, Yb³⁺ codoped colloidal α-NaYF₄ core-shell nanoparticles.

Lanthanide doped, up-converting nanoparticles have found considerable interest as luminescent probes in the field of bio-detection. Although the nanoparticles (NPs) have already been successfully applied for fluorescent bio-imaging and bio-assays, the efficiency of the up-conversion process seems to be the bottle-neck in rigorous applications. In this work, we have shown enhancement of the up-conversion in colloidal α-NaYF₄:Yb(3+), Tb(3+) doped nanocrystals owing to passivation of their surface.