Nanocomposites based on lanthanide-doped upconversion nanoparticles: diverse designs and applications

Abstract

Lanthanide-doped upconversion nanoparticles (UCNPs) have aroused extraordinary interest due to the unique physical and chemical properties. Combining UCNPs with other functional materials to construct nanocomposites and achieve synergistic effect abound recently, and the resulting nanocomposites have shown great potentials in various fields based on the specific design and components. This review presents a summary of diverse designs and synthesis strategies of UCNPs-based nanocomposites, including self-assembly, in-situ growth and epitaxial growth, as well as the emerging applications in bioimaging, cancer treatments, anti-counterfeiting, and photocatalytic fields. We then discuss the challenges, opportunities, and development tendency for developing UCNPs-based nanocomposites.

Tandem fabrication of upconversion nanocomposites enabled by confined protons

“…It should be mentioned that organic linkers, such as CA and PAA, are commonly used for the surface engineering of UCNPs for bioimaging and composite fabrication. 18,25 Although ligand-exchange reaction also can decorate CA and PAA on UCNPs, our design can be more facile and effective, because proton generators can remove the native oleate ligands, creating ligand-free UCNPs in situ which facilitates the further functionalization of organic linkers. 30 Furthermore, taking advantage of the linker, ternary nanocomposites, such as UCNPs-linker-EuOOH, can be obtained when EuOOH nanomaterials are introduced together with UCNPs (Fig.…”

“…19 Despite the advantages of UCNP-based nanocomposites, fabrication of the nanocomposites in a simple and controllable way is still challenging. 13,25,36 Generally, to construct uniform UCNP-based nanocomposites with desired properties, UCNPs are first synthesized and then modified for further fabrication. [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] UCNPs modified through both ligand exchange and intercala- His current research involves the investigation of inorganic functional nanomaterials, such as rare earth-doped luminescent nanomaterials, for bioapplications, catalysis, and sensing.…”

Lanthanide-Doped Upconversion Nanoparticles: Exploring A Treasure Trove of NIR-Mediated Emerging Applications

“…Advances in theranostics, using UCNPs, have been an active area of research as discussed by Chen and co-workers . Other related applications of UCNPs in photocatalysis and cancer therapeutics have also been detailed by Zhang and co-workers . UCNPs have thus been well-exploited for in vitro (as nanosensors for biomarkers) and in vivo applications (as luminescent tags for bioimaging). ,− While many of these traditional applications of upconversion, such as theranostics and analytical probe design, have exploited key advantages of UCNPs, other new areas remain underexplored.…”

Vacuum-Assisted Strong Luminescence Thermal Enhancement in NaYF4:Ho3+/Yb3+ Upconverting Nanocrystals: A Conclusive Evidence for the Effect of Water Desorption

“…Energy transfer upconversion (ETU) of Yb 3+ and Ln 3+ (Ln 3+ = Er 3+ , Tm 3+ , Ho 3+ ) codoped upconverting phosphors has been extensively studied for their unique nonlinear optical properties. − In 2014, Shao et al reported thermally enhanced upconversion luminescence (UCL) in Er 3+ /Yb 3+ codoped upconverting nanocrystals (UCNCs). Since then, the luminescence thermal enhancement (LTE) in lanthanide-doped UCNCs has received considerable attention due to its potential applications in anticounterfeiting, temperature sensing, thermochromism display technology, and so on. − There are several mechanisms proposed for LTE. − Yb–O surface phonons are considered to be responsible for LTE in NaYF 4 :Yb,Tm nanocrystals (NCs) through activating the surface dark-layer by enhancing energy transfer from Yb 3+ . , An interesting mechanism was employed for LTE of NaY­(WO 4 ) 2 , namely, thermal desorption of water from the NC surface. − This mechanism is supported by the observation of LTE suppression for NCs in dry nitrogen.…”