RESUMEN
As a remote and non-contact stimulus, light offers the potential for manipulating the polarization of ferroelectric materials without physical contact. However, in current research, the non-contact write-read (erase) process lacks direct observation through the stable current as output signal. To address this limitation, we investigated the photoinduced polarization switching capabilities of the cyanide-bridged compound [Fe2Co] using visible light, leading to the achievement of rewritable polarization. By subjecting [Fe2Co] crystals to alternating irradiation with 785 nm and 532 nm light, the polarization changes exhibited a distinct square wave pattern, confirming the reliability of the writing and erasing processes. Initialization involved exposing specific crystal units to 532 nm light for storing "1" or "0" information, while reading was accomplished by scanning the units with 785 nm light, resulting in brief current pulses for "1" states and no current signal for "0" states. This research unveils new possibilities for optical storage systems, paving the way for efficient and rewritable data storage and retrieval technologies, such as the next-generation memories.
RESUMEN
Nonlinear optical (NLO) crystals are widely applied in information technology, micro-manufacturing and medical treatment. Herein, a new lead mixed halide with strong second-harmonic generation (SHG) response, Cs3 Pb2 (CH3 COO)2 Br3 I2 , has been designed and rationally synthesized. Cs3 Pb2 (CH3 COO)2 Br3 I2 represents the rare NLO crystal featuring that three different anions (I- , Br- and O2- ) simultaneously coordinate the Pb(II) atom to form a severely distorted [PbBr2 I2 O2 ] polyhedron with a large polarizability. Remarkably, Cs3 Pb2 (CH3 COO)2 Br3 I2 not only exhibits a very strong phase-matching SHG response of 9×KH2 PO4 (KDP), but also possesses a large birefringence (0.27@1064â nm) and high laser damage threshold (LDT). The strong SHG effect of Cs3 Pb2 (CH3 COO)2 Br3 I2 mainly originates from the oriented arrangement of [Pb2 Br3 I2 ] chains. This study points out an effective strategy to develop new NLO crystals with strong SHG response.
RESUMEN
The discovery of new nonlinear optical (NLO) crystals with excellent properties is in urgently demand because of their ability to generate coherent light. Herein, we report an unique NLO lead bromide formate, KCs2 [Pb2 Br5 (HCOO)2 ], which has been synthesized by a mix-solvothermal method. KCs2 [Pb2 Br5 (HCOO)2 ] exhibits strong phase-matching second-harmonic generation (SHG) response (6.5×KDP), large birefringence (0.16@ 1064â nm), and a wide transparent window in most visible light and mid-IR region. Interestingly, KCs2 [Pb2 Br5 (HCOO)2 ] features a polar 3D lead-bromide framework in which adjacent Pb-Br layers containing coplanar Pb6 Br6 rings are not only parallel to each other, but also orient in the same direction. These oriented arrangements are responsible for the strong SHG response and large birefringence that are elucidated by both local dipole moment and theoretical calculations. This research provides a new strategy to explore subsequent NLO crystals.
RESUMEN
Nonlinear-optical (NLO) crystal is an important photoelectric functional material. In this work, a new NLO titanium iodate, (H3O)2Ti(IO3)6, along with Ti(IO3)4 has been synthesized under facile conditions. The space group of (H3O)2Ti(IO3)6 is the chiral noncentrosymmetric group R3 (No. 146), with an interesting three-dimensional framework, while that of Ti(IO3)4 is the centrosymmetric space group P1Ì (No. 2) containing one-dimensional chains. Thermogravimetric analysis shows that (H3O)2Ti(IO3)6 and Ti(IO3)4 have no weight loss below 220 and 390 °C, respectively. In addition, (H3O)2Ti(IO3)6 not only is thermally stable up to 200 °C in an air atmosphere but also is stable in water. (H3O)2Ti(IO3)6 has a moderate-intensity second-harmonic-generation (SHG) response (1.4×KDP), a large laser-induced damage threshold (46×AgGaS2), and high transmittance in the wavelength ranges of 0.5-1.4 and 2.5-10 µm. Both local dipole moment and systematic theoretical calculations reveal that the SHG response of (H3O)2Ti(IO3)6 is mainly because of the combined effect of [TiO6] octahedra and IO3 and IO4 units. In a word, (H3O)2Ti(IO3)6 exhibits good NLO performances, as well as water resistance and facile growth of a single crystal with high quality, indicating its potential application as NLO materials in the visible and mid-IR regions, especially the visible region.
RESUMEN
Nonlinear optical (NLO) crystals are the key component in solid-state lasers. New second-harmonic generation (SHG) effective halides, Cs3 Pb2 (CH3 COO)2 X5 (X=I, Br), have been rationally synthesized by introducing acetate groups into lead halide perovskites under moderate solvothermal conditions. Cs3 Pb2 (CH3 COO)2 X5 (X=I, Br) feature highly oriented anionic chains constructed by distorted [PbX4 O2 ] (X=I, Br) polyhedrons. Both the theoretical studies and the dipole moment calculations uncover that their SHG effects are mainly originated from the distorted [PbX4 O2 ] (X=I, Br) polyhedrons. Remarkably, Cs3 Pb2 (CH3 COO)2 I5 exhibits strong phase-matching SHG response (8×KDP) and large birefringence (0.26@ 1064â nm). Moreover, Cs3 Pb2 (CH3 COO)2 X5 (X=I, Br) also possess high laser damage threshold (LDT) which are almost 27 and 41 times that of AgGaS2 , respectively.
RESUMEN
Two new isostructural non-centrosymmetric cerium iodates KxCe9(IO3)36 (x≈ 3) and LaxCe9(IO3)36 (x≈ 0.3) were synthesized via a hydrothermal method and systematically characterized. They are intermediate valence compounds with the same band gap, showing similar microscopic net dipole moments per unit volume, but different macroscopic second-harmonic generation (SHG) responses under 1064 nm laser irradiation. This research gives a new view for understanding the effects of electronic structure on the SHG response.
