Themed collection Photon Upconversion Materials

Guest editors Eva Hemmer, Nobuo Kimizuka, Łukasz Marciniak, Lea Nienhaus and Timothy Schmidt introduce this Journal of Materials Chemistry C themed collection on photon upconversion materials.

Infrared (IR) to visible up-conversion devices made by incorporating IR detectors with visible emitting units are able to directly convert IR light into visible light.

In this work, we report the first example of lifetime thermometry with a molecular upconverter.

The emission intensity of individual upconverting nanoparticles (UCNPs) on metal surfaces is determined by an interplay between quenching and reflection effects, while the ratiometric thermometry signal is unaffected by the underlying material.

We demonstrate that the lowest triplet energy of many technologically relevant molecules can be inexpensively calculated. This will be particularly useful for triplet–triplet annihilation and singlet fission applications.

We synthesized a theranostics-integrated nanocomposite capable of switching between upconversion luminescence imaging and photothermal therapy/photodynamic therapy/NO gas therapy by changing the wavelength of near-infrared light irradiation.

Multifunctional core@shell type FeS₂@NaYF₄:Yb³⁺,Er³⁺ nanocomposites emit bright, color tunable UC photoluminescence and magnetic activity. We confirmed optical temperature sensing capability and rarely reported sensing of the laser power density.

Negative thermal expansion compounds provide an opportunity to understand the nature of thermal expansion and engineering applications of inorganic solid functional materials. This work gives a suitable case to investigate the relationship between thermal expansion and luminescence thermal behavior.

Design principles of Cu(I) complexes to induce thermally activated delayed fluorescence (TADF) behaviour with an electron-rich carbene moiety are elucidated by means of time-resolved luminescence and high-quality quantum chemical calculations.

A novel series of donor–acceptor–heavy-atom (D–A–H) molecules that simultaneously implement both photoinduced electron transfer and heavy atom effect strategies.

The role played by high concentration doping of Er³⁺ ions under 1550 nm excitation and the response mechanism of Ho³⁺ ions to 1550 nm photons.

Giant enhancement of anti-quenching upconversion luminescence is achieved in the Sc₂W₃O₁₂:Er³⁺/Yb³⁺ phosphors by (KMg)³⁺ impurity doping, and the phosphors are used for the construction of an all-fiber temperature sensing system.

Fluorescent microspheres exhibit unique emissions at the microscale and have been widely used as probes for immunoassays and advanced micro-sensors.

A multimode high sensitivity fluorescence thermometer combining fluorescence thermal enhancement and FL thermal extension in one NTE material Y₂Mo₃O₁₂:Nd³⁺,Yb³⁺.

Er³⁺/Yb³⁺ are distributed in a double-layer structure, blocked by a single layer of Sc³⁺/La³⁺. Red UCL intensity of (Gd_0.8Er_0.1Yb_0.1)(La_0.9Sc_0.1)O₃ is comparable to β-NaYF₄:Er³⁺/Yb³⁺.

Solid-state green-to-blue upconversion is shown in organic–inorganic hybrid ureasil hosts using the palladium(II) octaethylporphyrin and diphenylanthracene sensitizer/emitter pair, with emission retained for >70 days without deoxygenation.

Because of their well-defined light–matter interaction volume, high-quality single-crystalline nature, and precise bandgap tunability, all-inorganic cesium lead halide (CsPbX₃ (X = Cl, Br, I)) perovskite (IHP) microplates are of fundamental and technological interest today.