Fe³⁺-codoped ultra-small NaGdF₄:Nd³⁺ nanophosphors: enhanced near-infrared luminescence, reduced particle size and bioimaging applications

Abstract

Small-sized lanthanide-doped nanoparticles (NPs) exhibiting superior near-infrared (NIR) luminescence properties are highly desired for bioimaging applications.

Nanomaterials for light-mediated therapeutics in deep tissue

“…Metal ion doping, such as Li + , Ca 2+ , Fe 3+ , Zn 2+ , Mn 2+ and Na + , into the lattice could improve upconverting and downconverting luminescence through different mechanisms. 103,[128][129][130][131][132][133][134] On the other hand, PLNP intensity and afterglow time are enhanced by creating defects in the crystal lattice. 135 Substituting NaYF 4 :Yb 3+ /Tm 3+ with Ca 2+ caused a 121-fold improvement in upconversion luminescence intensity.…”

Opportunities for Persistent Luminescent Nanoparticles in Luminescence Imaging of Biological Systems and Photodynamic Therapy

“…NIR excitation has attracted much attention due to its deeper penetration in the biological tissues [ 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ]. Usually, the up-conversion (UC) phenomenon, followed by energy transfer, is used to induce persistent luminescence using NIR radiation [ 254 ].…”

“…Using the same analogy that the grass represents a cell, we will achieve what is shown in Figure 1 d. Because there is no continuous illumination, all the emission background is eliminated, and we can locate where the luminescent compound is located. Thus, the application of PeL materials eliminates the background emission and depth penetration problems, resulted from the excitation wavelengths in the UV-Vis, commonly used in luminescence imaging of biological systems [ 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ].…”

“…Because there is no continuous illumination, all the emission background is eliminated, and we can locate where the luminescent compound is located. Thus, the application of PeL materials eliminates the background emission and depth penetration problems, resulted from the excitation wavelengths in the UV-Vis, commonly used in luminescence imaging of biological systems [55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71][72]. Theranostics corresponds to systems capable of simultaneously treat (therapy) and diagnose (diagnostics) diseases.…”

A low-temperature self-flux route to prepare hexagonal rare earth fluorides and manipulation of upconversion luminescence in rodlike NaYbF4:Tm3+/Fe3+ crystals

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Recently, Fe 3+ doping has attracted increasing interest based on the following aspects. [14][15][16][17][18][19][20][21][22] First and foremost, Fe 3+ is a low-cost, nontoxic and harmless trivalent non-rare-earth metal ion, which gives it considerable appeal in a great number of areas including energy storage, quantum information processing, classic data storage, magnetic resonance imaging and spin-controlled reactions. There is one more point, and most importantly, the substitution of Fe 3+ for Yb 3+ can induce a change in the local crystal lattice field around rare earth ions stemming from the difference in the ionic radii of Fe 3+ and Yb 3+ , as expected, enhancing the f-f radiative transition rates and their UC emissions.…”