Near-infrared upconversion of Nd through Gd-mediated interfacial energy transfer in core-shell nanoparticles

Controlling upconversion in emerging multilayer core–shell nanostructures: from fundamentals to frontier applications

“…[16][17][18][19][20][21] The control of photon upconversion through core-shell nanostructures also advances the research in the new conceptual models like energy migration mediated upconversion (EMU) and interfacial energy transfer (IET) that greatly expands the observation of photon upconversion from more lanthanide ions (e.g., Eu 3+ , Tb 3+ , Dy 3+ , Sm 3+ , Ce 3+ and Nd 3+ ) and some transition metal ions (e.g., Mn 2+ ) apart from conventional ones (e.g., Er 3+ , Tm 3+ and Ho 3+ ). [22][23][24][25][26][27][28][29][30] So far, the upconversion emissions covering the ultraviolet (UV), visible (Vis) and near-infrared (NIR) spectral regions have been easily accessible, [31][32][33][34] consequently showing remarkable advantages in the fields ranging from biological imaging, therapeutics and neuroscience to nanophotonics. 17,[35][36][37][38][39][40][41][42][43][44][45][46] Among the various kinds of luminescent nanomaterials, multi-layer core-shell (MLCS) nanostructure UCNPs are a class of recently developed nanomaterials which have attracted special attention because of their much better flexibility and functionality with rational designs in size, composition, nanostructure and surface properties.…”

A Comparative Study of SiO2:Tb3+@Gd2O3:Eu3+ and Its Inverted Tb3+-Eu3+ Core–Shell Phosphors

“…It is well known that codoping has been widely used in adjustable multicolor luminescence and florescent enhancement. − Much effort has been made to improve the energy transfer efficiency and luminous intensity effectively. , In recent years, more and more energy transfer phenomenon at the core–shell interface has been reported, which has been studied extensively in up- and down-conversion luminescence field. − Instead of adding sensitizers and activators together to the core or shell traditionally, , they added them separately to the core and shell, and the luminescence intensity and energy transfer efficiency can be improved by IET. Chandra Babu et al synthesized SmPO 4 @SiO 2 :Eu 3+ core–shell red phosphors by sol–gel method and proved the existence of energy transfer from Sm 3+ to Eu 3+ .…”