Simultaneous Realization of Phase/Size Manipulation, Upconversion Luminescence Enhancement, and Blood Vessel Imaging in Multifunctional Nanoprobes Through Transition Metal Mn²⁺ Doping

Abstract

A strategy is demonstrated for simultaneous phase/size manipulation, multicolor tuning, and remarkably enhanced upconversion luminescence (UCL), particularly in red emission bands in fi xed formulae of general lanthanidedoped upconverting nanoparticles (UCNPs), namely NaLnF 4 :Yb/Er (Ln: Lu, Gd, Yb), simply through transition metal Mn 2+ -doping. The addition of different Mn 2+ dopant contents in NaLnF 4 :Yb/Er system favors the crystal structure changing from hexagonal (β) phase to cubic (α) phase, and the crystal size of UCNPs can be effectively controlled. Moreover, the UCL can be tuned from green through yellow and to dominant red emissions under the excitation of 980 nm laser. Interestingly, a large enhancement in overall UCL spectra of Mn 2+ doped UCNPs (∼59.1 times for NaLuF 4 host, ∼39.3 times for NaYbF 4 host compared to the UCNPs without Mn 2+ doping) is observed, mainly due to remarkably enhanced luminescence in the red band. The obtained result greatly benefi ts in vitro and in vivo upconversion bioimaging with highly sensitive and deeper tissue penetration. To prove the application, a select sample of nanocrystal is used as an optical probe for in vitro cell and in vivo bioimaging to verify the merits of high contrast, deeper tissue penetration, and the absence of autofl uorescence. Furthermore, the blood vessel of lung of a nude mouse with the injection of Mn 2+ -doped NaLuF 4 : Yb/ Er UCNPs can be readily visualized using X-ray imaging. Therefore, the Mn 2+ doping method provides a new strategy for phase/size control, multicolor tuning, and remarkable enhancement of UCL dominated by red emission, which will impact on the fi eld of bioimaging based on UCNP nanoprobes.

Effect of molybdenum on upconversion emission and temperature sensing properties in Na0.5Bi0.5TiO3:Er/Yb ceramics

“…It can be observed that the FIR value increased gradually with increasing the temperature and reached its maximum value at 553 K. The experimental data can be well fitted with Eq. (1) and the values of coefficient and energy gap were found to be $ 6.67 and 706.68 cm À 1 , respectively. For optical thermometry applications, the sensing sensitivity was estimated from the equation of S ¼ dR/dT ¼ R(ΔE 12 /kT 2 ) [23,24].…”

“…Over the past decade, enormous interest in rare-earth (RE) ions doped materials has been gained owing to their wide applications in luminescent label for bioimaging, color displays, white lightemitting diodes, etc [1][2][3]. Some interesting phenomena, such as enhanced piezoelectricity, photoluminescence (PL), and upconversion (UC) emission, were observed in RE ions doped ferroelectric ceramics [4][5][6][7].…”

A polymorphic lanthanide complex as selective Co2+ sensor and luminescent timer

“…S12a-h), even when there were as many as 209 points (detail data are listed in Table 3). Since lanthanide complexes have many applications in bio-labeling, bio-imaging and photodynamic therapy, the property of timer may enhance the potential application of lanthanide complexes in the field of online bio-monitoring, protein tracking or biomarkers [50,51].…”

Multifunctional hollow CaF2:Yb3+/Er3+/Mn2+-poly(2-Aminoethyl methacrylate) microspheres for Pt(IV) pro-drug delivery and tri-modal imaging

“…The quenching effect of Mn 2þ ions is probably ascribable to the depopulation of nonradiative energy transfer from the Er 3þ to Mn 2þ ( 2 H 9/2 / 4 S 3/2 / 4 T 1 ), especially at high doping concentration of Mn 2þ ions [72]. In our study, we find that the largest emission intensity can be achieved when UCNPs doping 2.5% Mn 2þ ions, the emission intensity of which is 1.49 times than that of undoped UCNPs [39,43,60,63]. And the red to green intensity ratio (I R /I G ) increases from 3.42 to 3.97.…”