RESUMO
Borates and fluorooxoborates are advanced optical materials with great potential applications in the ultraviolet (UV) and deep ultraviolet (DUV) regions. Herein, two new UV optical crystals K6B12O19F4 and K12B28O48 were synthesized. Among them, K6B12O19F4 has a rare disorder of BO3 and BO4 units, which is the first time this disordered type has been found in fluorooxoborates. In this paper, the properties of K6B12O19F4 and K12B28O48 were tested and calculated, and their crystal structures and structural evolution were carefully analyzed. In addition, the effects of metal cations size and F ions on the crystal structure were analyzed. This research enriches the structural chemistry of borates and fluorooxoborates, and provides experience for the design of new UV optical crystals.
RESUMO
Parallel nanomaterials possess unique properties and show potential applications in industry. Whereas, vertically aligned 2D nanomaterials have plane orientations that are generally chaotic. Simultaneous control of their growth direction and spatial orientation for parallel nanosheets remains a big challenge. Here, a facile preparation of vertically aligned parallel nanosheet arrays of aluminum-cobalt oxide is reported via a collaborative dealloying and hydrothermal method. The parallel growth of nanosheets is attributed to the lattice-matching among the nanosheets, the buffer layer, and the substrate, which is verified by a careful transmission electron microscopy study. Furthermore, the aluminum-cobalt oxide nanosheets exhibit high-temperature ferromagnetism with a 919 K Curie temperature and a 5.22 emu g-1 saturation magnetization at 300 K, implying the potential applications in high-temperature ferromagnetic fields.
RESUMO
A mixed alkali-metal nonlinear optical (NLO) dihydro-cyanurate crystal Rb3Na(H2C3N3O3)4·3H2O has been synthesized via the hydrothermal method. Its calculated birefringence is about 0.368, which is very large, its ultraviolet (UV) cutoff edge is down to 230 nm, and the powder second harmonic generation (SHG) intensity is about 0.2 × KDP. In addition, a first-principles investigation of the electronic properties on Rb3Na(H2C3N3O3)4·3H2O was carried out. The calculated band gap and SHG coefficient values agree well with the experimental ones. These results suggest that it could be applied as a UV birefringent material.
