Linear and nonlinear optical properties of trigonal borate crystals K7MIn2-xYbx(B5O10)3 (M = Ca, Sr, Ba; x=0…2) with isolated B5O10 units

Noncentrosymmetric borates K7MIn2−xYbx(B5O10)3 (M = Ca, Sr, Ba; x = 0…2) were synthesized by the solid state reaction and the crystals were successfully grown by the top seeded solution growth method using the K2O-B2O3-MF2 flux. According to Rietveld refinement, the crystal structure belongs to the noncentrosymmetric R32 space group. Also, the octahedrally coordinated In atoms are located at wide ranges ∼8 Å which may be promising for phosphor and laser applications. Samples with ytterbium show a characteristic emission band in the range of 950–1050 nm related to the 2F5/2 → 2F7/2 transition of Yb3+ ions that is commonly used for laser generation. IR, Raman and absorption spectra were obtained for the samples as well. The short cut edge of UV absorption, SHG intensity comparable with KDP and low concentration quenching of luminescence suggest that the K7MIn2−xYbx(B5O10)3 borates are promising self-frequency doubling materials

Synthesis and growth of rare earth borates NaSrR(BO3)2 (R = Ho− Lu, Y, Sc)

NaSrR(BO3)2(R = Ho-Lu, Y, Sc) compounds were obtained for the first time. Their structures exhibit disordered positions of Sr2+and Na+ atoms while RO6polyhedra are connected through the BO3 groups. Large distances between R atoms and high transparency in the range of 250-900 nm make them promising for phosphor applications. A pathway to obtain single crystals was shown by growing NaSrY(BO3)2and NaSrYb-(BO3)2by the top seeded solution growth method with Na2O-B2O3-NaFflux

Study of RBO3-ScBO3 phase diagrams and RSc3(BO3)4 orthoborates (R = La, Pr and Nd)

RBO3 – ScBO3 diagrams (R = La, Pr and Nd) were investigated by the solid state synthesis and DSC methods. In these systems the solid solutions based on RSc3(BO3)4, RBO3 and ScBO3 were identified. The single crystals of RSc3(BO3)4 were grown by spontaneous crystallization method from LiBO2-LiF flux. The borates containing Pr and Nd have typical luminescence in the red/IR range which correlated to Pr3+: 3P0 → 3H6, 1D2 → 3H4 (~ 620 nm), and 3P0 → 2F2, 1D2 → 3H5 (~ 655 nm) and Nd3+ electron transitions 4F3/2 → 4I9/2 (875 nm) and 4F3/2 → 4I11/2 (1055 nm). The luminescence intensity strongly depends on the concentration of the fluorophores. In addition the SHG efficiency (for radiation of Nd:YAG laser, 1064 nm) for grown PrSc3(BO3)4 crystals was found to be 1.85 times higher (deff) than for KDP revealing its high potential for various NLO application

Study of an EuBO3–ScBO3 system and EuSc3(BO3)4, EuSc(BO3)2 orthoborates

The EuBO3–ScBO3 system was investigated by solid state synthesis and DSC methods. In this system, a new EuSc(BO3)2 compound was found. It crystallizes in the R3¯ space group with unit cell parameters of a = 4.8939(1) Å and c = 16.2663(5) Å. Whereas another compound in the system EuSc3(BO3)4 possesses two modifications: a low-temperature α-C2/c (a = 7.687(1) Å, b = 9.810(2) Å, c = 12.021(2) Å, and β = 105.379(4)°) and a high-temperature β-R32 (a = 9.7473(1) Å and c = 7.9205(2) Å). The α-EuSc3(BO3)4 crystal was grown with LiBO2–LiF flux, and β-EuSc3(BO3)4 was obtained by the solid state synthesis. All of the obtained crystals exhibited typical Eu3+ luminescence spectra with peaks at 589 nm, 596 nm, 615 nm, 657 nm and 689 nm, which corresponded to the 5D0 → 7FJ ( J = 0, 1, 2 and 4) electron transitions. The strongest peak of luminescence was located at 615 nm and corresponded to the 5D0 → 7F0 transition

Study of an SmBO3–ScBO3 system and new SmSc(BO3)2 orthoborate

A new SmSc(BO3)2 compound was discovered from the study of SmBO3–ScBO3 by solid-state synthesis. The obtained compound was grown from a stoichiometric melt by a spontaneous crystallization method, and crystallizes in the space group R3¯ with the cell parameters of a = 4.8951(6) Å and c = 16.3012(2) Å. In addition, phase equilibria in this system in the 900–1300 °C temperature range were studied by X-ray diffraction and thermal analyses, as well as special diffusion experiments

Polymorphism in SmSc3(BO3)4: Crystal structure, luminescent and SHG properties

Low temperature C2/c and high temperature P321 modifications of SmxSc4-x (BO3)4 solid solutions were grown from LiBO2eLiF flux. These borates have typical luminescence for Sm3þ containing crystals with the two strongest peaks at 602 and 645 nm, which correspond to 4G5∕2 / 6H7∕2, 6H5∕2 electron transitions. In addition, the compounds were characterized by IR and Raman spectroscopy. SHG intensity for trigonal modification was found to be three times higher than that of KDP revealing its high potential for various NLO applications