Absorption and Emission Spectra of Ni-Doped Glasses and Glass-Ceramics in Connection with Its Co-Ordination Number

Abstract

The absorption and emission spectra of Ni-doped glasses and transparent glass-ceramics are discussed in relation to its coordination number. The results evidenced that the color changed drastically to deep pink from yellow for the lithium metasilicate crystal based transparent glass-ceramics and to blue from brown for the spinel crystal based transparent glass-ceramics after crystallization, respectively. The absorption spectra of lithium metasilicate and Spinel glasses suggest the existence of a tetrahedral Ni 2 ion and a trigonal bipyramid Ni 2 ion. On the contrary, tetrahedral Ni 2 ions in the lithium metasilicate transparent glass-ceramics and the octahedral Ni 2 ion in Spinel transparent glass-ceramics are dominant. The emission at around 580 nm was observed in Spinel transparent glass-ceramics under the excitation of 380 nm, however, a very weak or no emission was observed in the lithium metasilicate glass, lithium metasilicate transparent glass-ceramics and Spinel glass under the excitation of 430 nm. This emission might be due to a 1 T 1 D q 3 A 2 F transition after the excitation from 3 A 2 F to 3 T 1 P of the octahedral Ni 2 ions. In addition, only Spinel transparent glass-ceramics exhibits a broad NIR emission at around 1220 nm under the excitation of a 974 nm laser diode. This emission may be due to 3 T 2 F q 3 A 2 F transition. It is considered that the tetrahedral Ni 2 ion is located between the chains in the lithium metasilicate crystal.

Laser patterning of oriented LiNbO3 crystal particle arrays in NiO‐doped lithium niobium silicate glasses

“…In NiO‐doped LNS glasses, the absorption band with a strong intensity at around 430 nm and a broad band centered at around 800 nm are observed. These peaks are typical for Ni 2+ ions in glasses . The coordination of Ni 2+ ions is very sensitive to their ligand field environments and is still controversial .…”

“…These peaks are typical for Ni 2+ ions in glasses . The coordination of Ni 2+ ions is very sensitive to their ligand field environments and is still controversial . Galoisy et al proposed that in silicate glasses showing brown color, Ni 2+ ions have trigonal bipyramid fivefold coordinated (NiO 5 ) sites and there is no indication of significant amounts of octahedral sixfold coordinated (NiO 6 ) Ni 2+ ions.…”

“…Moreover, they proposed that the NiO 5 polyhedra are not strongly associated with the polymer network, that is, no Ni‐O‐Si linkage with strong covalent bonds . Trigonal bipyramid fivefold coordinated Ni 2+ ions have typical optical absorption bands at 430 nm and around 800 nm, and therefore, it is analyzed that Ni 2+ ions in LNS glasses are present mainly as the trigonal bipyramid fivefold coordination state. There has been no report on the coordination state of Ni 2+ ions in 40Li 2 O‐32Nb 2 O 5 ‐28SiO 2 glass, in which a large amount of Li 2 O and Nb 2 O 5 (network modifiers) are included and the content of SiO 2 (network former) is small.…”

Zn$$_{1-x}$$Ni$$_x$$Te semiconductor nanocrystals in transparent glass for optoelectronic device applications

“…3 19 . The nature and position of the bands are associated to the fivefold coordinated Ni in trigonal pyramid ( Ni ) and tetrahedral ( Ni ) sites and bulk property of ZnTe-like NCs 16 , 33 . In the G sample absorption spectrum, the observed bands around 435, 826, and 1963 nm are the characteristic bands of fivefold coordinated Ni in trigonal pyramid ( Ni ) sites, and the band around 1356 nm is associated to the tetrahedral ( Ni ) sites.…”

Optical properties of 3d N transition metal ion-doped lead borate glasses

“…High alkali borate and borosilicate glasses favor the existence of tetrahedral Ni 2+ , while low alkali borate and borosilicate glasses prefer the presence of octahedral Ni 2+ , and these are pink and green-blue in color, respectively. The electronic ground state of Ni 2+ in octahedral symmetry is 3 A2g( 3 F), with the excited states 3 T2g( 3 F), 1 Eg( 1 D), 3 T1g( 3 F), 1 T2g( 1 D), broad band near infrared emission from Ni 2+ -doped glasses [25][26][27].…”