Effects of Cr3+ concentration on the optical properties of Cs2NaAlF6 single crystals

Abstract

a b s t r a c tThis work is devoted to the study of optical properties of the elpasolite Cs 2 NaAlF 6 with 0.1, 1.0, 3.0, 10.0, 30.0 and 50.0% of Cr 3 þ ions. The interest in this system lies on the fact that it presents a high quantum yield in the visible and infrared regions and therefore can be considered for laser applications. The photoluminescence and excitation spectra were obtained at 5 and 300 K, while the absorption spectra were measured at 300 K. The spectra at 300 K show broad bands attributed to the Cr 3 þ ions in two non-equivalent sites, both of them with octahedral coordination, while at 5 K we can observe the vibrational modes of the [CrF 6 ] 3 À complex. The ensemble of our results lead us to conclude that the material has potential applications as a lasing system.

Brilliant green dye added zinc(tris) thiourea sulphate monocrystal growth with enhanced crystalline perfection, optical, photoluminescence and mechanical properties

“…The grown crystals are belongs to high band gap materials category which makes them favorable applicant for optoelectronic device applications [38,[50][51][52]. and another violet-blue emission band at *420 nm (broad), which may be attributed to creation of S 2-vacancies due to dye doping as a results of vacancy sites and defect concentrations [53][54][55]. It is interesting to be noted here that the PL intensity of UV emission has been remarkably enhanced, which may be due to increase in vacancy related defects (F-centers) in the doped crystals that acts as color centers.…”

Cs2NaAl1−xCrxF6: A family of compounds presenting magnetocaloric effect

“…From low-temperature luminescence experiments it is known that the vibrational lines are not shifted in relation to the zero-phonon line when the doping level is increased [27], indicating that the Cr 3+ impurity concentration does not have significant influence on the lattice vibrational modes [42]. In this way, it can be seen that the difference between the values of θ D and θ E for both concentrations is not enough to cause a significant change in the lattice vibrational modes.…”

“…Other successful examples consist of perovskite-type oxides [11], metal-organic frameworks containing gadolinium [12], and molecular nanomagnets, such as Mn 32 [13] and Fe 14 [14]. However, very few studies have so far reported on caloric effects in fluoride systems [15][16][17], which is the aim of this paper.From the point of view of optical and structural properties, Cs 2 NaAl 1−x Cr x F 6 elpasolite single crystals, which crystallize in the R3m space group, have been thoroughly investigated [18][19][20][21][22][23][24][25][26][27]. The choice of the Cr 3+ ion as a doping impurity is justified by the fact that its 3d unfilled shell produces electronic transitions that increase the luminescent properties and the quantum yield of the material [20,[27][28][29].…”

“…From the point of view of optical and structural properties, Cs 2 NaAl 1−x Cr x F 6 elpasolite single crystals, which crystallize in the R3m space group, have been thoroughly investigated [18][19][20][21][22][23][24][25][26][27]. The choice of the Cr 3+ ion as a doping impurity is justified by the fact that its 3d unfilled shell produces electronic transitions that increase the luminescent properties and the quantum yield of the material [20,[27][28][29].…”

“…The choice of the Cr 3+ ion as a doping impurity is justified by the fact that its 3d unfilled shell produces electronic transitions that increase the luminescent properties and the quantum yield of the material [20,[27][28][29].…”