Citric acid-assisted phase controlled synthesis of NaYF4:Yb3+,Tm3+ crystals and their intense ultraviolet upconversion emissions

Development of ultrasensitive and As(iii)-selective upconverting (NaYF4:Yb3+,Er3+) platform

Solid-phase, LRET-based NaYF₄:Yb³⁺,Er³⁺ platform for the ultrasensitive (1 nM) detection of arsenic.

Highly efficient near-infrared light photocatalytic hydrogen evolution over MoS2 supported Ta2O5 combined with an up-conversion luminescence agent (β-Tm3+,Yb3+:NaYF4/MoS2–Ta2O5 nanocomposite)

The photocatalytic hydrogen evolution activity of Ta₂O₅ can be greatly enhanced by adding up-conversion luminescence agent (β-Tm³⁺,Yb³⁺:NaYF₄) and co-catalyst (MoS₂).

Controllable self-assembly of NaREF4 upconversion nanoparticles and their distinctive fluorescence properties

The paper presents the growth of hexagonal NaYF4:Yb(3+), Tm(3+) nanocrystals with tunable sizes induced by different contents of doped Yb(3+) ions (10%-99.5%) using the thermal decomposition method. These nanoparticles, which have different sizes, are then self-assembled at the interface of cyclohexane and ethylene and transferred onto a normal glass slide. It is found that the size of nanoparticles directs their self-assembly. Due to the appropriate size of 40.5 nm, 15% Yb(3+) ions doped nanoparticles are able to be self-assembled into an ordered inorganic monolayer membrane with a large area of about 10 × 10 μm(2). More importantly, the obvious short-wave (300-500 nm) fluorescence improvement of the ordered 2D self-assembly structure is observed to be relative to disordered nanoparticles, which is because intrinsic absorption and scattering of upconversion nanoparticles leads to the self-loss of fluorescence, especially the short-wave fluorescence inside the disordered structure, and the relative emission of short-wave fluorescence is reduced. The construction of a 2D self-assembly structure can effectively avoid this and improve the radiated short-wave fluorescence, especially UV photons, and is able to direct the design of new types of solid-state optical materials in many fields.

Simple synthesis of amino acid-functionalized hydrophilic upconversion nanoparticles capped with both carboxyl and amino groups for bimodal imaging

Amino acid-functionalized hydrophilic upconversion nanoparticles capped with both carboxyl and amino groups were one-step synthesized for bimodal imaging.