Spectral and thermometric properties altering through crystal field strength modification and host material composition in luminescence thermometers based on Fe³⁺doped AB₂O₄type nanocrystals (A = Mg, Ca; B = Al, Ga)

Abstract

The influence of the crystal field strength and host material composition on the spectral position of the emission band and thermal stability of Fe3+ luminescence was investigated in order to develop a highly sensitive luminescence thermometer.

Highly efficient Fe3+-doped A2BB′O6 (A = Sr2+, Ca2+; B, B′ = In3+, Sb5+, Sn4+) broadband near-infrared-emitting phosphors for spectroscopic analysis

“…Although the luminescence of Fe 3+ with intraconfigurational d–d transitions has been reported, the emission commonly occurs in the red and far-red light regions depending on the local environment of Fe 3+ in the host materials 22 – 26 . Almost no Fe 3+ -doped phosphors exhibit NIR emission exceeding 800 nm, except for the recently reported CaAl 12 O 19 :Fe 3+ (808 nm), SrAl 12 O 19 :Fe 3+ (811 nm), and CaGa 2 O 4 :Fe 3+ (809 nm) 27 – 29 . Typically, tetrahedrally coordinated Fe 3+ ions emit in the 650−750 nm range, whereas octahedrally coordinated ones are expected to exhibit longer NIR emission wavelengths 30 .…”

Two Selective Sites Control of Cr3+‐Doped ABO4 Phosphors for Tuning Ultra‐Broadband Near‐Infrared Photoluminescence and Multi‐Applications

“…Besides, no obvious characteristic absorption bands of Cr 4+ (600 and 1160 nm) appear in Figure 2a, indicating no transition of Cr 4+ ions exists in the system. [ 15c ] The obvious redshift of absorption bands suggests that cation substitution in the ABO 4 host lattice has strong influence on the crystal field around Cr 3+ 3d orbitals. Besides, the color change of powder body in Figure 2a is owing to the changes of absorption in the visible light region (400–800 nm).…”

“…The emission shift by modifying the local crystal field strength caused by a change in the chemical composition of the matrix was previously described for various transition metal ions such as: Fe 3+ , Ni 2+ , and Cr 3+ . [ 4d,15 ] Herein, based on crystallographic site engineering and crystal field regulation, a series of tunable NIR emission from 825 to 1025 nm with broadened FWHM from 125 to 231 nm are realized in (Ga,Sc,In)(Ta,Nb)O 4 :Cr 3+ solid solutions, which is quite a large spectral tuning for NIR emission. Moreover, benefited from the 200 nm tuning and broadened FWHM of 104 nm, potential multi‐applications of ABO 4 :Cr 3+ phosphors in NIR spectroscopy detection, night vision, and penetrating biology tissue are verified.…”

Analysis on the microstructure and magnetic properties of MgGaFeO4 spinel compound

“…Studies on polycarbosilanederived SiC ceramic 25 and SiC/SiC composite 26,27 have shown that porosity decreases and mechanical properties improve with the increasing number of PIP cycles. Zhu et al 28 show that increasing pyrolysis temperature and the concentration of SiC fillers in polycarbosilane polymer result in improved mechanical properties in two-dimensional Carbon/ SiC (C/SiC) composites fabricated using the PIP process.…”

“…Nowadays, there are many studies on spinel ferrites MgFe 2 O 4 or MgGa 2 O 4 , in which the intensive focus is on the performance characterization and application potential, but lacking of some theoretical researches. [27][28][29][30] However, based on the relative literature researches, the investigation on MgGaFeO 4 has not been reported so far, and thus it is necessary to carry out an in-depth research on MgGaFeO 4 . The appropriate proportion of Ga-doped MgGaFeO 4 can reduce the Curie temperature to a suitable range that many interesting magnetic measurements are accessible.…”