Optical absorption and electron paramagnetic resonance studies of Cr3+-doped Y3Ga5O12 phosphor

Two-Site Occupation for Exploring Ultra-Broadband Near-Infrared Phosphor—Double-Perovskite La2MgZrO6:Cr3+

“…The asymmetric signal at g = 4.22 is attributed to isolated Cr 3+ ions, whereas the intense signal at g = 1.97 is assigned to the Cr 3+ –Cr 3+ exchange coupled pairs. It has been reported that similar resonances of Cr 3+ -isolated ions or coupled pairs appear in octahedral sites of glasses and crystals. − The ESR result indicates that chromium ions are stabilized in a trivalent state and tend to stay adjacent corresponding to cosubstitution of Zr 4+ and Mg 2+ because of no extra charge imbalance, which is consistent with discussions before.…”

Ultrawide near‐infrared SrHfO3:Cr3+ phosphor with dual emission bands

“…The asymmetric signal at g = 4.32 is attributed to isolated Cr 3+ ions, whereas the signal at g = 1.92 is assigned to the Cr 3+ –Cr 3+ exchange coupled pairs. The similar resonances of Cr 3+ ‐isolated ions or coupled pairs were reported in glasses and crystals 27–29 . These results validate that Cr ions are accommodated in the host lattice and stabilized in a trivalent state.…”

“…The similar resonances of Cr 3+ -isolated ions or coupled pairs were reported in glasses and crystals. [27][28][29] These results validate that Cr ions are accommodated in the host lattice and stabilized in a trivalent state.…”

Design Principles for 3d Electron Transfer in a Ga-Based Garnet To Enable High-Performance Reversible Thermochromic Material Color Maps

“…The optical properties of all samples were studied by UV–vis and NIR (200 nm < λ < 1200 nm) diffuse reflectance and absorption spectra, and the spectra (Kubelka–Munk transformed reflectance) are displayed in Figure . The spectra of Er 3 Ga 5 O 12 show a number of absorption bands, which are at 355.6, 362.5, 378.3, 406.2, 441.2, 449.9, 486.7, 525.0, 542.5, 652.6, 787.2, and 962.0 nm, originating from the Er 3+ transitions between the ground state ( 4 I 15/2 ) and excited states ( 4 G 7/2 , 4 G 9/2 , 4 G 11/2 , 2 H 9/2 , 4 F 3/2 , 4 F 5/2 , 4 F 7/2 , 2 H 11/2 , 4 S 3/2 , 4 F 9/2 , 4 I 9/2 , and 4 I 11/2 ). − Compared with other transitions, the 4 I 15/2 → 2 H 11/2 transition has a high intensity, complies with the selection rules |Δ L | ≤ 2, |Δ J | ≤ 2, and Δ S = 0, and is known as a hypersensitive transition. , Figure a shows that the changes in the absorption behavior of Cr 3+ -doped samples are the additions of two wide absorption bands at 441.2 and 612.4 nm, which were related to Cr 3+ d–d transitions, , and the absorption intensity gradually increased with an increase in the Cr 3+ doping amount. − The absorption bands at 441.2 and 612.4 nm correspond to 4 A 2g → 4 T 1g and 4 A 2g → 4 T 2g transitions of Cr 3+ in the octahedral site, respectively. − On the basis of the optical properties, the colors of Cr 3+ -doped samples are attributed to the Cr 3+ d–d transition in purple and orange regions, and the green color gradually became deeper with an increase in the Cr 3+ doping amount, findings in agreement with the absorption band for the d–d transition becoming gradually stronger. Figure b shows the absorption behavior of Mn 3+ -doped samples.…”