A long persistent phosphor based on recombination centers originating from Zn imperfections

Triple‐Mode Emissions with Invisible Near‐Infrared After‐Glow from Cr3+‐Doped Zinc Aluminum Germanium Nanoparticles for Advanced Anti‐Counterfeiting Applications

“…The blue band between 360 and 640 nm is similar to that from ZnAl 1.4 Ge 0.3 O 3.7 (ZAG) nanoparticles without Cr 3+ (Figure S3, Supporting Information) and associated with Zn vacancies in Zn‐Al‐Ge‐O. [ 26 ] The narrow red band from 670 to 760 nm arises from the 2 E → 4 A 2 spin‐forbidden transition of Cr 3+ in the octahedron. [ 27,28 ] The NIR emission is slightly enhanced with increasing annealing temperature up to 1200 °C.…”

Folic acid-conjugated chromium(III) doped nanoparticles consisting of mixed oxides of zinc, gallium and tin, and possessing near-infrared and long persistent phosphorescence for targeted imaging of cancer cells

“…The excitation spectrum consisted of three excitation bands, a stronger one centered about 254 nm and two weaker one around 430 and 583 nm, respectively. In view of the intensity differences, the former vests in the band-to-band transition, whereas the latter correspond to the crystal-field transitions, 4 A 2 → 4 T 1 (t 2 e) and 4 A 2 → 4 T 2 (t 2 e) of Cr 3+ [27,28]. The bright red to NIR fluorescence and long persistent phosphorescence were also visually evaluated by using a high resolution digital camera and supersensitive NIR camera in a dark room (Fig.…”

Tailoring of the trap distribution and crystal field in Cr3+-doped non-gallate phosphors with near-infrared long-persistence phosphorescence

“…ESR signals were all observed to decrease as the test intervals increased, indicating that (i) the detected ions or defects are responsible for electron storage; (ii) with increasing Al content, trap types vary dynamically as a result of different structural environment settings. 39 In addition, ESR spectra of ZS3, ZS7, ZS9 and ZS10 samples measured 1 min after irradiation ended at 100 K are also shown in Figure 4c. It is observed that the ESR spectrum exhibits an intense resonance signal with g Manipulation via ligand field strength So far, we have confirmed that Cr 3+ only appears at the octahedral sites of Sn 4+ or Zn 2+ with a weak crystal field in Zn 2 SnO 4 .…”

“…Alternatively, the concentration variation of the captured and released electrons is triggered at different measurement time intervals. 39 TL intensities as a function of Al doping content measured 30 s after the end of irradiation are shown in Figure 3b. In contrast to the TL peak position, we confirm the typical TL intensity pattern of an initial decrease (samples ZS3-ZS6) followed by an increase (samples ZS6-ZS9) and final decrease again (samples ZS9-ZS10), which is consistent with the variation in the persistence time.…”