Effect of detrapping on up-conversion charging in LaMgGa11O19:Pr3+ persistent phosphor

Up-conversion charging of a Tb3+-activated garnet phosphor

“…28 Such a quadratic fit also implies that there is no saturation effect in the trapping/detrapping process upon illumination with the present doses. 29 As pointed out above (Fig. 2), besides the 488 nm excitation, the UCC process of the Gd 2.7 Tb 0.3 Ga 5 O 12 phosphor can be achieved upon 375 nm illumination.…”

“…Up-conversion charging (UCC) is an alternative approach for charging persistent phosphors upon visible or infrared illumination. 24–30 In a typical UCC process for phosphors, the electron traps are filled via a two-step ionization of the activator. So far UCC has been achieved in Cr 3+ , Mn 2+ and Pr 3+ -activated phosphors.…”

“…So far UCC has been achieved in Cr 3+ , Mn 2+ and Pr 3+ -activated phosphors. 23–30 According to the electronic structure and energy-level scheme, Tb 3+ is also a potential activator ion for achieving the UCC process. In an appropriate phosphor, the Tb 3+ ion has a tendency to oxidize and its 5 D 4 state acts as an intermediate state to promote the up-conversion excitation process.…”

Time-Gated Imaging of Latent Fingerprints with Level 3 Details Achieved by Persistent Luminescent Fluoride Nanoparticles

“…Persistent luminescent (PersL) materials are capable of photon emission lasting for seconds, minutes, or even hours after ceasing the excitation light source. − Such ultralong-lived emission, which is much different from traditional luminescence, results in the emergence of time-gated imaging technology with zero background fluorescence. Q. Yuan and co-workers proposed a time-gated imaging strategy by using Zn 2 GeO 4 :Ga,Mn PersL nanoparticles and achieved background-free visualization of glycoproteins in LFPs .…”

Multichannel Control of PersL/Upconversion/Down-Shifting Luminescence in a Single Core–Shell Nanoparticle for Information Encryption

“…Persistent luminescence (PersL) is an interesting phenomenon, which is able to release the energy in form of light emission with a long time duration (from a few seconds to days), showing great promise in applications of temperature dosimeters, optical storage, and information anticounterfeiting. − Such a slow luminescence process results from the controllable release of irradiation energy trapped in the matrix. − Typical PersL materials include SrAl 2 O 4 :Eu 2+ /Dy 3+ , Ca 2 Al 2 SiO 7 :Pr 3+ , Zn 3 Ga 2 Ge 2 O 10 :Cr 3+ , and LaMgGa 11 O 19 :Pr 3+ with emissions ranging from ultraviolet (UV) to visible and near-infrared regions. − Compared to traditional luminescent materials, a unique feature of PersL materials is that they can be precharged before being deployed in biological systems. This can avoid autofluorescence or background scattering induced by the excitation light, resulting in clearer imaging of biological tissues together with long-term usage. , In addition, the design of core–shell nanoparticles facilitates their functionalization, such as multiwavelength excitable luminescence. , Although this can be obtained in the powder materials based on the codoping scheme, the complex cross-relaxation processes would cause serious energy loss with a resultant significant decrease in luminescence intensity. − Using the epitaxial growth method, a reasonable core–shell structure design can integrate more excitation–emission modes with multicolor output on a single nanoparticle level. − However, the current excitation light sources used for PersL are usually high-energy X-rays, and the materials are mostly limited to bulk or powder phosphors, which cannot be applied to biological applications.…”