Simultaneous ultraviolet-C and near-infrared enhancement in heterogeneous lanthanide nanocrystals

Abstract

Lanthanide-doped nanocrystals that simultaneously converted near-infrared (NIR) irradiation into emission at shorter (ultraviolet-C, UVC) and longer wavelengths (NIR) offer many exciting opportunities for drug release, photodynamic therapy, deep-tissue bioimaging, and...

Near-infrared light responsive intensified multiphoton ultraviolet upconversion in nanostructures towards efficient reactive oxygen species generation

“…The above results indicate that the critical separation distance from Nd 3+ to ICG is 4.4 nm, which is in line with previously reported works. 26,38…”

“…The above results indicate that the critical separation distance from Nd 3+ to ICG is 4.4 nm, which is in line with previously reported works. 26,38 It is now widely recognized that coating an inert layer on the surface of UCNPs can greatly improve their upconversion emission performance by inhibiting the surface quenching effect. [39][40][41] It can be clearly seen that the lifetime of emitter Tm 3+ ions at 361 nm and 447 nm in ICG-sensitized nanocrystals coated with the LiYF 4 inert layer was overwhelmingly extended in contrast to that of those nanocrystals without the LiYF 4 outermost layer (Fig.…”

“…25 Subsequent works found that the first shell-layer NaYF 4 :Yb in the above nanostructure plays a vital role in enhancing UV emission, which greatly inhibited the energy consumption caused by the internal energy traps and maximized the cascade sensitization upconversion effect of NIR excitation. 26 In addition to designing the core–shell structure, there are also other strategies that can be used to improve the UV emission performance of UCNPs, such as changing the symmetry of the crystal field by ion doping, 27 and promoting the absorption ability of excitation light by designing nanocavity 28 and integrated optical microring resonators. 29 Although efficient UV emission under 808 nm excitation can be realized by using such effective strategies, the resultant serious synthesis failure risk of multi-layer structures and complex experimental designs further limits their practical application.…”

The effect of triethylamine on dye-sensitized upconversion luminescence and its application in nanoprobes and photostability

“…[2][3][4][5] Especially, cyanine dyes can attach onto the surface of lanthanide-doped upconversion nanoparticles (UCNPs) to enhance the upconversion luminescence. [6][7][8][9][10][11] In 2012, Hummelen's group took cyanine dye IR806, whose main absorption wavelength is between 650 and 850 nm with a high absorption coefficient of 390 lg À1 cm À1 at 806 nm, as the sensitizer of b-NaYF 4 :Yb 3+ ,Er 3+ UCNPs. 12 Under excitation at 800 nm, the upconversion brightness was increased by 1100 times.…”

Degradation of upconverting nanoparticles in simulated fluids evaluated by ratiometric luminescence

“…[1][2][3][4][5][6][7][8][9][10][11] The proposal and application of core-shell upconversion nanostructures is a milestone in the development of upconversion nanomaterials, which provides exciting new opportunities for their wide application in the biomedical, [12][13][14][15][16] environmental, and photocatalysis fields. [17][18][19][20][21] Notably, Liu's group proposed an energy transfer-mediated upconversion mechanism, in which activators without long-life intermediate energy states (Tb 3+ , Eu 3+ , Dy 3+ and Sm 3+ ) were doped in separated layers to achieve tunable upconversion emission by controlling gadolinium sublattice-mediated energy migration. 22 The rational design of a core-shell nanostructure not only enhances the luminescence [23][24][25] but also integrates multiple functional units into a single UCNP, [26][27][28] thus providing great flexibility for the construction of UCNPs.…”