Oxyfluoride Glass-Ceramics for Transition Metal Ion Based Photonics: Broadband Near-IR Luminescence of Nickel Ion Dopant and Nanocrystallization Mechanism

Abstract

Nickel ion doped transparent bulk glass-ceramics containing K 2 SiF 6 , ZnF 2 , and KZnF 3 nanocrystals were elaborated to show the prospect that this novel group of oxyfluoride glass-ceramics is promising for transition metal ion based photonics. These new oxyfluoride glass-ceramics exhibit a new broadband luminescence of Ni 2+ ions in the intriguing near-IR spectral region ranging from 1200 to 2400 nm. Ni 2+ ions are incorporated into the precipitated K 2 SiF 6 , ZnF 2 , and KZnF 3 crystals, which provide octahedral sites for Ni 2+ and make it optically active. Taking into account the microstructure of phase separation observed by replica TEM, a detailed mechanism of phaseseparation-assisted nanocrystallization was described for these oxyfluoride glasses. These results allow one to establish a full physical model of the nanocrystallization mechanism. For the precipitation of fluoride crystallites, not only can the nanometric size be explained but also the formation of different crystal phases can be controlled by the initial amorphous phase separation of droplet or interpenetrating structure with a sufficiently elaborated glass design.

Selective doping of Ni2+ in highly transparent glass-ceramics containing nano-spinels ZnGa2O4 and Zn1+x Ga2−2x Ge x O4 for broadband near-infrared fiber amplifiers

“…On the other hand, it is possible that the substitution of Ge 4+ for 6 Ga 3+ may generate octahedrally coordinated 6 Ge 4+ , which may in turn be substituted by Ni 2+ . However, considering the fact that only weak NIR emission was observed from the Zn 2 GeO 4 /Li 2 Ge 4 O 9 : Ni 2+ GCs, and the large mismatch in valence and ionic radii between 6 Ni 2+ and 6 Ge 4+ (ionic radius: 0.53 Å), the substitution of 6 Ni 2+ for 6 Ge 4+ is severely limited, akin to the partition of Ni 2+ in K 2 SiF 6 nanocrystals embedded GCs 17 . Moreover, no NIR emission related to the tetrahedrally coordinated 4 Ni 2+ , e.g., Ni 2+ doped Zn 2 SiO 4 or Zn 2 GeO 4 crystals, has been recorded even at cryogenic temperatures 36 .…”

Crystallization control in Ni2+‐doped glass‐ceramics for broadband near‐infrared luminesce

“…In the past several years, numerous optical investigations have been conducted on Ni 2+ ‐doped oxyfluoride glass‐ceramics. For example, broadband luminescence at 1550 and 1750 nm has been reported in the Ni 2+ ‐doped oxyfluoride glass‐ceramics embedded with Rb 2 SiF 6 and KZnF 3 nanocrystals . The full width at half maximum (FWHM) of these material candidates is only around 500 nm.…”

Instant precipitation of KMgF3:Ni2+ nanocrystals with broad emission (1.3‐2.2 μm) for potential combustion gas sensors

“…After thermal treatment, obvious changes occurred including the absorption bands position. The color of sample doped with 0.5 NiO changes and the 0.5GCs present different characteristic absorption bands of Ni 2+ in octahedral sites . The specific positions of these absorption bands vary remarkably.…”

“…Compared to the study of RE‐doped oxyfluoride GCs, reports on similar TM doping are still rare . For example, broadband emission covering 1300‐2200 nm with FWHM of 350 nm is known from perovskite KZnF 3 :Ni 2+ embedded in a GC …”