Discovery of non-reversible thermally enhanced upconversion luminescence behavior in rare-earth doped nanoparticles

Abstract

Volatilization of surface moieties and sintering of the particles both contribute to thermally activated enhancement of upconversion emission.

Thermal enhancement of upconversion emission in nanocrystals: a comprehensive summary

“…Meanwhile, Qiu's group reported the thermally enhanced UCL in core-only Yb 3+ /Tm 3+ β-NaGdF4 UCNPs. It was found that the particle sintering process proceeded at high temperatures (>500 K) and caused the irreversible thermal enhancement of UCL 56 (Fig. 5c-d).…”

Hydrothermal Synthesis and Up‐conversion Luminescence of Ho3+/Yb3+ Co‐doped PbTiO3

“…With the deepening of the studies on the up‐conversion of rare earth (RE) doped materials recently, it has shown great potential in the fields of temperature sensing, anti‐counterfeiting technology and biological imaging . The lanthanide RE ions becomes an excellent choice for up‐conversion luminescence, because of their multistage metastable energy level structure.…”

Inflection in size-dependence of thermally enhanced up-conversion luminescence of UCNPs

“…23 In this regard, it is easy to accept that heating-induced desorption of water molecules from UCNPs’ surfaces can naturally lead to the alleviation of surface quenching. 24,25 The amount of water molecules that can be absorbed (desorbed) to (from) the surfaces of UCNPs is directly associated with, again, the surface-to-volume ratio. Since smaller UCNPs featuring a higher surface-to-volume ratio will absorb more water molecules and suffer more serious surface quenching, more dissipation energy will be recovered by means of the heating-induced desorption of water molecules from smaller UCNPs.…”