Ultrafast Synthesis of Novel Hexagonal Phase NaBiF₄ Upconversion Nanoparticles at Room Temperature

Abstract

Upconversion (UC) nanoparticles (UCNPs) have evoked considerable attention in many fields owing to their fascinating features. However, rigorous synthesis conditions and expensive raw materials often limit their further applications. Here, a novel hexagonal phase NaBiF UC matrix through a very facile method (one min only at room temperature) is synthesized. The nanoparticles show good monodispersity with uniform size. Under the 980 nm irradiation, Yb /Ln (Ln = Er, Ho, Tm) codoped NaBiF nanoparticles show excellent UC luminescence (UCL). This super facile synthesis strategy and excellent matrix materials enable to achieve UCL in such low temperature, opening a new gateway for the UCNPs applied to a variety of areas in the future.

Extremely straightforward room temperature co-precipitation method to synthesize cubic KYF4:Yb/Er up-conversion nanoparticles in deionized water-ethanol solution

“…With further research, many advantages of UC nanomaterials have been presented, such as low autofluorescence background, the absence of blinking and photobleaching, superior photostability, tunable and sharp-band emission, long lifetimes, large anti-Stokes shifts and so on. [5][6][7][8][9][10] As a result, it was studied by many researchers. Among the multitude of reported host materials, especially the fluoride nanoparticles get much attention mainly for their low lattice phonon energy which can reduce thermal lensing effects under strong pumping conditions to reduce non-radiative losses and therefore enhance luminescence efficiency.…”

Laser excitation‐activated self‐propagating sintering of NaYbF4:Pr3+/Gd3+ white light microcrystal phosphors

“…With Gd 3+ ions concentration augmenting, the coordinate is getting closer to the standard of (0.33, 0.33) in the region of white light. It means that, under the same laser excitation intensity, Gd 3+ ions can tune the color of UCPL, promoting the white purity of as‐synthesized samples …”

Novel Bismuth‐Based Nanomaterials Used for Cancer Diagnosis and Therapy

“…Although significant progress has been made in this field, there still exists some challenges that need to be investigated and addressed to promote the practical application of theranostic Bi‐based NMs. (1) As multimodal imaging agents, more imaging modalities beyond CT and PA need to be integrated into single‐phase Bi‐based NMs so that they can be better used in clinical applications; (2) as radiation sensitizer, the safer Bi‐based NMs should be developed to avoid side effects brought about by radiation; (3) as PTT agents, the photothermal mechanism of Bi‐based NMs needs to be better understood to further improve their photothermal efficiency; (4) novel NIR‐triggered Bi‐based PDT agents still need to be designed to effectively generate ROS; (5) the safety of theranostic Bi‐based NMs is still at the initial stage of development and more studies are required before they can be applied in clinic; and (6) additional Bi‐based NMs, such as upconversion NaBiF 4 NPs, Bi 2 O 2 Se nanosheet with a narrow band gap (0.8 eV), and BiVO 4 , Bi 2 WO 6 NPs with excellent photoelectronic properties, should be involved into the design of theranostic platforms.…”

“…(5) the safety of theranostic Bi-based NMs is still at the initial stage of development and more studies are required before they can be appliedi nc linic;a nd (6) additional Bi-based NMs, such as upconversion NaBiF 4 NPs, [53] Bi 2 O 2 Se nanosheet with a narrow band gap (0.8 eV), [101] and BiVO 4 , [102] Bi 2 WO 6 [103] NPs with excellent photoelectronic properties, should be involved into the design of theranostic platforms.…”