Rapid microwave reflux process for the synthesis of pure hexagonal NaYF4:Yb3+,Ln3+,Bi3+ (Ln3+ = Er3+, Tm3+, Ho3+) and its enhanced UC luminescence

Li+ ions doping core–shell nanostructures: An approach to significantly enhance upconversion luminescence of lanthanide-doped nanocrystals

“…6. Each decay curve can be well fitted into a single exponential functional I(t) = I 0 + A 1 exp(Àt/s), where I and I 0 are the luminescence intensities at time t and 0, A 1 is a constant and s is the lifetime [23]. As shown, the lifetimes of the 1 G 4 state for Tm, Tm-Li, Tm@ and Tm-Li@ samples were determined to be 0.46, 0.52, 0.66 and 0.98 ms, respectively.…”

“…Till now, numerous techniques have been adopted to further enhance UC emissions, including sensitizing mechanisms [15,16], crystal surface modifications [17,18], the formation of coreshell structure [19,20], the introduction of non-lanthanide ions [21][22][23][24][25][26] and the incorporation of noble-metals [27][28][29]. Among these methods, the growth of a shell surrounding the core is a common way to improve luminescence efficiency.…”

Simultaneous morphology manipulation and upconversion luminescence enhancement of β-NaYF4:Yb3+/Er3+ microcrystals by simply tuning the KF dosage

“…The remarkable challenge for us is how to further enhance the UC intensities of RE ions doped β-NaYF 4 crystals, which has considerable significance to their applications. So far, several attempts have been devoted to improving UC intensity via internal adjustment and external approaches, such as sensitizing mechanisms26, the formation of core-shell structure27, the introduction of non-lanthanide ions2829 and the incorporation of noble metals3031. Among these methods, co-doping with non-lanthanide ions provides an alternative approach to enhance UC luminescence intensity by adjusting the crystal field symmetry.…”

Multimodal Cancer Imaging Using Lanthanide-Based Upconversion Nanoparticles

“…So it is necessary to improve the luminescence intensity of UCNPs to meet the extremely high sensitivity requirements for bioassays and bioimaging. Up to date, several methods have been developed to enhance UC emission, including the manipulation of the dopant concentration [54][55][56], the control of particle size [57,58], the introduction of nonLn 3+ [59][60][61][62][63], the formation of core-shell structure [64][65][66][67][68][69][70][71][72][73][74][75][76][77][78][79][80][81][82][83] and the incorporation of noble-metals [84][85][86]. Some of these approaches have already been presented by previous review articles [87,88].…”