Monodisperse, size-tunable and highly efficient β-NaYF4:Yb,Er(Tm) up-conversion luminescent nanospheres: controllable synthesis and their surface modifications

Synthesis of β-Phase NaYF4:Yb,Er Upconversion Nanocrystals and Nanorods by Hot-Injection of Small Particles of the α-Phase

“…During the last years, a large number of research papers was pub-lished on the synthesis of NaREF 4 nanocrystals (RE = rare-earth), since NaREF 4 and LiREF 4 are attractive host lattices for a variety of functional optical materials such as upconversion phosphors, [6][7][8][9][10][11][12][13][14] quantum-cutting phosphors, [15][16][17][18][19] laser materials, [20,21] and materials for solar cell applications [22][23][24][25][26]. A variety of synthetic methods has been described for producing solvent-dispersible sodium rare-earth tetrafluoride nanocrystals with controlled size, shape and capping ligand, including thermal decomposition, [7,[27][28][29][30][31][32] co-precipitation, [6,11,[33][34][35][36][37][38][39][40] or solvothermal methods [41][42][43][44][45][46][47]…”

Upconversion fluorescence resonance energy transfer—a novel approach for sensitive detection of fluoroquinolones in water samples

“…This peak is assigned to the C=O stretching vibration of the -COOH groups of the PAA. The shoulder observed at 2955 cm − 1 associated with the asymmetrical stretching mode of -CH 3 groups became inconspicuous after ligand exchange [42,51,55,56]. Based on FT-IR spectra and the good dispersal of UCPs in water after PAA exchange, they can be considered as the direct evidences for the exchange ligand process.…”

“…The hexagonal phase NaLuF 4 is often synthesized in organic solvents under high temperature or by using suitable dopants. Gd 3+ was added to the system in order to increase the upconversion luminescence and for the reduction of particle size [36,42,44,47]. The shapes of the particles are highly influenced by the crystallographic phase of the initial seeds that have been formed during the nucleation process.…”

“…The method was mainly based on the previously reported works [39,42]. Typically, a mixture of PAA (0.5 g) and DEG (10 mL) was heated at 110°C under vigorous stirring (500 rpm) for 10 min.…”

Multimodal Light-Harvesting Soft Hybrid Materials: Assisted Energy Transfer upon Thermally Reversible Gelation

“…Such quenching effects have been demonstrated unequivocally in the case of water molecules and other alcohols. 55,56 It is also important to mention that the fibrillary network avoids the clustering of the UCNPs, leading to a more homogeneous and uniform luminescent material. Additionally, the scattering of IR light in the supramolecular gel could also enlarge the interaction of the laser with the UCNPs, contributing to the observed emission.…”