Fluorescence property of novel near-infrared phosphor Ca2MgWO6:Cr3+

Broadband near-infrared (NIR) emission realized by the crystal-field engineering of Y3−xCaxAl5−xSixO12:Cr3+(x= 0–2.0) garnet phosphors

“…The concentration quenching occurring at y = 0.6% can be ascribed to energy transfer between the adjacent Cr 3+ ions by multipole-multipole interactions, exchange interactions or re-absorption. 20,47 In addition, the maximum emission of the broadband shifts from 738 to 768 nm when the Cr 3+ concentration increases from y = 0.1% to 1.0%. The red-shift can be attributed to the re-absorption of Cr 3+ .…”

“…As the strength of the crystal field decreases, the broadband emission attributed to the spinallowed 4 T 2 -4 A 2 transition appears. 18 Several kinds of broadband phosphors with weak crystal fields have been reported recently, such as SrSc 2 O 4 :Cr, 19 Ca 2 MgWO 6 :Cr, 20 ScBO 3 :Cr, 21 and Sr 8 MgLa(PO 4 ) 7 :Cr. 22 In addition, broadband emissions can be achieved by decreasing the crystal field strength of a strong crystal field material by a substitution strategy.…”

Optimization of the Synthesis and Energy Transfer of Ca2MgWO6:Cr3+,Nd3+

“…For all three samples, the three expected spin-allowed [Ar]3d 3 -[Ar]3d 3 transitions of Cr 3+ having the electron configuration [Ar]3d 3 were observed. These were in the UV range with its center at 345 nm ( 4 A 2 → 4 T 1 ( 4 P)), in the green spectral range with its center at 475 nm ( 4 A 2 → 4 T 1 ( 4 F)), and in the deep red spectral range with its center at 694 nm ( 4 A 2 → 4 T 2 ( 4 F)) [17]. The sample 10 in which no charge compensation was present showed a slightly worse reflectivity, whereas the other two samples (2 and 11) had identical reflection spectra.…”

“…Figure 2c shows the reflection spectra of Ca 2 MgWO 6 samples co-doped with Cr 3+ and Nd 3+ , where the charge was balanced with different amounts of Li + /Na + (samples 4 and [15][16][17][18]. In contrast to Ca 2 MgWO 6 :Cr 3+ and Ca 2 MgWO 6 :Nd 3+ , another very broad absorption band was recorded, which only occurred if Cr 3+ and Nd 3+ were present at the same time.…”

“…Xu et al studied CMW:Cr 3+ and CMW:Cr 3+ ,Yb 3+ . It turned out that Cr 3+ in this host material can be very efficiently excited in the ultraviolet range [17,18].…”