Lab on upconversion nanoparticles: optical properties and applications engineering via designed nanostructure

Abstract

Over the past decade, high-quality lanthanide doped upconverting nanoparticles (UCNPs) have been successfully synthesized with the rapid development of nanotechnology. Due to the unique electron configuration of lanthanide ions, there are rich energy level structures in the near-infrared, visible and ultraviolet spectral range. However, for UCNPs, only a limited number of efficient upconversion excitation and emission have been generated due to the limited number of sensitizer (Yb(3+)) and activator (Tm(3+), Er(3+), and Ho(3+)) ions, and the application is mainly focused on the bio-imaging by using the upconversion luminescence of UCNPs. Recently, more and more researchers have started to focus on tuning of upconversion optical properties and developing of multi-functional UCNPs by using the combination of sub-lattice mediated energy migration, core@shell structural engineering and UCNPs based nanocomposites which greatly expands the range of applications for lanthanide-doped UCNPs. Therefore, a "nanolab" can be created on UCNPs, where the property modulation can be realized via the designed host-dopants combinations, core@shell nanostructure, energy exchange with "alien species" (organic dyes, quantum dots, etc.), and so on. In this paper, we provide a comprehensive survey of the latest advances made in developing lanthanide-doped UCNPs, which include excitation and emission energy levels guided designing of the UCNP nanostructure, the synthesis techniques to fabricate the nanostructure with optimum energy level structure and optical properties, the fabrication of UCNPs-based nanocomposites to extend the applications by introducing the additional functional components, or integrating the functional moiety into one nanocomposite.

Polyaniline-coated upconversion nanoparticles with upconverting luminescent and photothermal conversion properties for photothermal cancer therapy

“…31 Thus, lanthanidebased upconversion nanoparticles (UCNPs) have special optical characteristics, such as sharp emission lines, large anti-Stokes shifts of several hundred nanometers, and the absence of autofluorescence in biosamples. [32][33][34][35][36][37][38] Therefore, UCNPs have been recently used as building blocks in the construction of multimodal contrast agents for imagingguided therapy. [39][40][41][42][43][44][45] In the current study, upconversion nanoparticles (UCNPs) were first prepared by a typical solvothermal method.…”

Recent Advances on Functionalized Upconversion Nanoparticles for Detection of Small Molecules and Ions in Biosystems

“…Because of the fast exploration of UCNPs, several reviews have already summarized the preparation and applications of UCNPs 23, 37, 38, 39, 40, 41, 42, 43, 44, 45. In this review, we mainly focus on recent achievements on the usage of lanthanide‐doped UCNPs as efficient probes for biodetection since 2014.…”

Influence of Mn Doping on the Sensing Properties of SnO<sub>2</sub> Nanobelt to Ethanol

“…It is well known that the dopant of rare metals may improve the sensitive performance of nanomaterials [16]. For instance, Li et al have reported that the sensitivity of Er-doped SnO 2 nanobelt device is 9 to the formaldehyde gas [17].…”