Themed collection Editor’s Choice Collection: Photon Upconversion

Associate Editor, Professor Xiaogang Liu (National University of Singapore), introduces this Editor's Choice collection in Nanoscale on photon upconversion.

Molecular photosensitizers (PS) allow to exploit visible (Vis) and near-infrared (NIR) light for photocatalytic production of solar fuels, organic synthesis and environmental remediation.

Recent efforts for alleviating energy dissipation and enhancement of energy collection are reviewed to combat thermal quenching in UCNPs.

The development of lanthanide-doped non-contact luminescent nanothermometers operating in the biological windows spectral regions, the strategies to improve their thermal sensitivities, and their applications have been reviewed.

The recent achievements in luminescent nanomaterials used in optical and optoelectronic data storage have been reviewed.

Cell–cell communication is important for cellular differentiation, organ function, and immune responses.

Biicosahedral Au₂₅ clusters exhibit room-temperature phosphorescence from the excited triplet state with an intersystem crossing quantum yield of almost 100%. This property allows triplet sensitization and induces triplet fusion photon upconversion.

The first example of green (λ > 500 nm)-to-ultraviolet (λ < 400 nm) triplet–triplet annihilation-based photon upconversion sensitized by lead halide perovskite nanocrystals is achieved.

A method for video-rate display with optimized single UCNP brightness by integrating the full emission intensity over excitation time and lifetime.

NaYF₄ and LiYF₄ nanoparticles co-doped with Pr³⁺ and Yb³⁺ are reported, manifesting 980 nm excited downconversion luminescence peaked at 1320 nm for NIR-II bioimaging and 447 nm excited upconversion luminescence at 275 nm for germicide action.

A dye-sensitized heterogeneous lanthanide nanocrystal regulates the energy transfer pathway for UVC and NIR enhancement under 793 nm excitation.

The photoluminescence quantum yield (PLQY) of NaGdF₄:Er³⁺/Yb³⁺ upconverting nanoparticles (UCNPs) as a function of size and shape is studied. Sub-20 nm α-phase UCNPs showed a higher PLQY compared to similar size β-phase UCNPs.

The concentration of hydroxyl impurities in fluoride-based core-shell nanocrystals can be minimized by epitaxial growth of spatially compressed shells under fluoride-rich conditions.

The surface chemistry of upconversion nanoparticles can effectively control the quenching effect of water molecules affecting the thermal dynamics of luminescence.

Dual magnetic and temperature optical probes of hierarchically structured core@multi-shell nanoparticles with controlled crystalline phases: a magneto cubic core containing Dy^III and a co-doped Er^III:Yb^III: Nd^III optical hexagonal shell.

This work sheds light on the pump power impact on the performance of luminescent thermometers, which is often underestimated by researchers.

We employ a single optically trapped upconverting nanoparticle (UCNP) of NaYF₄:Yb,Er of diameter about 100 nm as a subdiffractive source to perform absorption spectroscopy.

NIR laser scanning microscopy enables the determination of the emission lifetime of upconversion nanoparticles (UCNPs) and UCNP nanohybrids (UCNHs), and the evaluation of the homogeneity in terms of colocalization of UCNHs.

By virtue of the two-dimensional-like structure of Cs₂NaYF₆, we achieve efficient UV, red and green upconversion emissions of Tm³⁺, Eu³⁺ and Tb³⁺ in core-only Cs₂NaYF₆:Yb/Tm, Cs₂NaYF₆:Yb/Tm/Gd/Eu and Cs₂NaYF₆:Yb/Tm/Gd/Tb nanoplatelets, respectively.

Bipyramidal LiErF₄:Tm³⁺@LiYF₄ upconversion nanocrystals with high signal-to-noise ratio for plant cell imaging.

Core@shell nanoparticles showing up-conversion under 808, 975, 1208 or 1532 nm excitation were synthesised. Nanoparticles revealed their multifunctionality and emission bands covering the visible to near-infrared range (475 to 1625 nm).

Effective photothermal conversion is realized with NaScF₄: Yb³⁺/Er³⁺/Mn²⁺@NaScF₄@SiO₂@Cu₂S nanoparticles along with high resolution optical thermometry in real time.

We report a mechanistic strategy towards the tunable upconversion of holmium sublattice through interfacial energy transfer under both steady-state and non-steady-state excitations, showing great promise in anti-counterfeiting.

An experimental approach and associated model to derive the nanoscale thermal properties of a conformal lipid bilayer supported on an upconverting nanoparticle, and which yields fundamental biophysical properties of the lipid bilayer.

A NO-release platform based on upconversion dendritic mesoporous silica nanocomposites was invented for combined imaging-guided synergistic chemodynamic/photodynamic/gas therapy.

Convenient design of fully Yb-based upconversion nanoparticles enables control of their luminescence characteristics and enhances super-resolution imaging performance.