Co-precipitation synthesis and self-reduction of CaF 2 :Eu 2+ nanoparticles using different surfactants

Mineralogical Characteristics and Luminescent Properties of Natural Fluorite with Three Different Colors

“…The existence of REE will not only change the color of fluorite but also lead to the fluorescence and phosphorescence of fluorite [ 12 , 13 , 14 , 15 ]. Studies have shown that in addition to the common blue fluorescence, some fluorites also show fluorescence of other colors, such as yellow, yellow-green, green, and red [ 16 , 17 , 18 , 19 , 20 ]. The discussion on the luminescence mechanism of fluorite has continued to be in-depth [ 21 , 22 , 23 , 24 , 25 ].…”

Fluorescent Enhancement of CaF2: Nd3+ Nanoparticles through a Concentration‐Gradient Core/Shell Hybrid Structure

“…[10] Thirdly, CaF 2 has a well-known fluorite structure in which Ca 2 + ions lie at the nodes in a face-centred lattice, therefore Ca 2 + ion can be easily substituted by alkalic ions or trivalent lanthanide ions due to their similar ionic radius leading to the change of the symmetry. [11] Finally, charge compensation can be achieved by defect formation where Ca 2 + ion is substituted by alkalic ion or trivalent lanthanide ion. [11] However, the Ln 3 + doped MF 2 (where M = Ba 2 + , Sr 2 + , Ca 2 + ) NPs tend to form monodisperse nanospheres with ultra-small size of ∼ 5 nm in a solution system.…”

“…[11] Finally, charge compensation can be achieved by defect formation where Ca 2 + ion is substituted by alkalic ion or trivalent lanthanide ion. [11] However, the Ln 3 + doped MF 2 (where M = Ba 2 + , Sr 2 + , Ca 2 + ) NPs tend to form monodisperse nanospheres with ultra-small size of ∼ 5 nm in a solution system. [12] It remains a challenge for the following difficulties to synthesize ultra-small CaF 2 :Ln 3 + NPs that are highly emissive.…”

“…[13] Firstly, Ln 3 + doped MF 2 requires an extra F < M-> for charge compensation, while the introduction of such F À ions into the grain surface may induce transient electric dipoles with their negative poles outward and vast surface defection. [11] Secondly, the surface and interface atoms may be dominant for the properties for nanomaterials. [14] Surface atoms usually exist as unsaturated or dangling bonds, and heterostructure interfaces containing strain-induced defects.…”

“…It remains a challenge for the following difficulties to synthesize ultra‐small CaF 2 :Ln 3+ NPs that are highly emissive [13] . Firstly, Ln 3+ doped MF 2 requires an extra F < M‐> for charge compensation, while the introduction of such F − ions into the grain surface may induce transient electric dipoles with their negative poles outward and vast surface defection [11] . Secondly, the surface and interface atoms may be dominant for the properties for nanomaterials [14] .…”