Guanidinium Fluorooxoborates as Efficient Metal-free Short-Wavelength Nonlinear Optical Crystals

Abstract

Metal-free borates have emerged as a new class of solid-state chemistry and related crystalline materials with high performance. However, the discovery of metal-free borate crystals that can meet the phase-matching behavior in the short-wavelength ultraviolet (UV) spectral region is extremely limited. Against this background, two new guanidinium fluorooxoborates with the chemical formula of [C­(NH2)3]­[B3O3F2(OH)2] and [C­(NH2)3]2[B3O3F4(OH)] have been discovered and characterized as high-performance candidates for short-wavelength UV nonlinear optical (NLO) applications. The optimally aligned configuration of coplanar [C­(NH2)3] cations and [B3O3F2(OH)2]/[B3O3F4(OH)] heteroanionic units makes both crystals have a sufficiently large NLO coefficient, birefringence, and band gap, which indicate that both metal-free hydroxyfluorooxoborates are promising NLO crystals. The well-ordered configurations of OH/F anions in two borates were identified using various approaches, and the origin of high optical performance was validated by additional measurements and calculations. Our findings verified the feasibility of searching NLO crystals in the short-wavelength region in a metal-free borate system via an eco-friendly and low-cost way.

Performance of optical materials with the derivative of planar π-conjugated groups: Recent advances and future prospects

“…[C(NH 2 ) 3 ][B 3 O 3 F 2 (OH) 2 ] was obtained by the solution-evaporation method and belongs to the non-centrosymmetric space group P1 of the triclinic system. 82 From Fig. 16, [B ] was also synthesized via the solutionevaporation method and crystallizes in the non-centrosymmetric space group P1 of the triclinic system.…”

Na4Ga8S14: a Ga-enriched wide band gap ternary alkali-metal sulfide with unique [Ga12S42] 12-membered rings

“…36,37 Then, the Kubelka-Munk function, F(R) = α/S = (1 − R) 2 /2R (where F(R) is the ratio of absorption coefficient to scattering coefficient; α is the absorption coefficient; R the reflectance; S the scattering coefficient) was used to calculate the absorption spectrum from the reflection spectrum and the bandgap was determined. [38][39][40][41][42]…”

New Self-Organizing Optical Materials and Induced Polymorphic Phases of Their Mixtures Targeted for Energy Investigations

“…The position and spatial orientation of fluorine atom further influence properties of nematogenic materials. The physical characteristics of the resulting liquid crystalline material, such as melting and phase transition temperatures, mesomorphic morphology, dipole moment, and dielectric anisotropy, were significantly influenced by the combination of the lateral fluorine atom’s small size and high polarity [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”