Nonlinear optical (NLO) crystals with superior properties are significant for advancing laser technologies and applications. Introducing rare earth metals to borates is a promising and effective way to modify the electronic structure of a crystal to improve its optical properties in the visible and ultraviolet range. In this work, we computationally discover inversion symmetry breaking in EuBa3(B3O6)3, which was previously identified as centric, and demonstrate noncentrosymmetry via synthesizing single crystals for the first time by the floating zone method. We determine the correct space group to be
Nonlinear optical (NLO) materials are of intense academic and technological interest attributable to their ability to generate coherent radiation over a range of different wavelengths. The requirements for a viable NLO material are rather strict, and their discovery has mainly been serendipitous. This study reports synthesis, characterization, and, most importantly, growth of large single crystals of a technologically viable NLO material—Rb3Ba3Li2Al4B6O20F. Through the judicious selection of cations, Rb3Ba3Li2Al4B6O20F exhibits a 3D structure that facilitates the growth of large single crystals along the optical axis direction. Measurements on these crystals indicate that Rb3Ba3Li2Al4B6O20F exhibits a moderate birefringence of 0.057 at 1064 nm enabling Type I phase‐matching down to 243 nm. Theoretical calculations indicate the symmetry adapted mode displacement (SAMD) parameter scales with the second‐harmonic generation intensity.
more » « less- NSF-PAR ID:
- 10043784
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Optical Materials
- Volume:
- 5
- Issue:
- 23
- ISSN:
- 2195-1071
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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P 6¯. The material has a large direct bandgap of 5.56 eV and is transparent down to 250 nm. The complete anisotropic linear and nonlinear optical properties were also investigated with ad 11of ∼0.52 pm/V for optical second harmonic generation. Further, it is Type I and Type II phase matchable. This work suggests that rare earth metal borates are an excellent crystal family for exploring future deep ultraviolet (DUV) NLO crystals. It also highlights how first principles computations combined with experiments can be used to identify noncentrosymmetric materials that have been wrongly assigned to be centrosymmetric. -
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Ever-increasing demands for energy, particularly being environmentally friendly have promoted the transition from fossil fuels to renewable energy.1Lithium-ion batteries (LIBs), arguably the most well-studied energy storage system, have dominated the energy market since their advent in the 1990s.2However, challenging issues regarding safety, supply of lithium, and high price of lithium resources limit the further advancement of LIBs for large-scale energy storage applications.3Therefore, attention is being concentrated on an alternative electrochemical energy storage device that features high safety, low cost, and long cycle life. Rechargeable aqueous zinc-ion batteries (ZIBs) is considered one of the most promising alternative energy storage systems due to the high theoretical energy and power densities where the multiple electrons (Zn2+) . In addition, aqueous ZIBs are safer due to non-flammable electrolyte (e.g., typically aqueous solution) and can be manufactured since they can be assembled in ambient air conditions.4As an essential component in aqueous Zn-based batteries, the Zn metal anode generally suffers from the growth of dendrites, which would affect battery performance in several ways. Second, the led by the loose structure of Zn dendrite may reduce the coulombic efficiency and shorten the battery lifespan.5
Several approaches were suggested to improve the electrochemical stability of ZIBs, such as implementing an interfacial buffer layer that separates the active Zn from the bulk electrolyte.6However, the and thick thickness of the conventional Zn metal foils remain a critical challenge in this field, which may diminish the energy density of the battery drastically. According to a theretical calculation, the thickness of a Zn metal anode with an areal capacity of 1 mAh cm-2is about 1.7 μm. However, existing extrusion-based fabrication technologies are not capable of downscaling the thickness Zn metal foils below 20 μm.
Herein, we demonstrate a thickness controllable coating approach to fabricate an ultrathin Zn metal anode as well as a thin dielectric oxide separator. First, a 1.7 μm Zn layer was uniformly thermally evaporated onto a Cu foil. Then, Al2O3, the separator was deposited through sputtering on the Zn layer to a thickness of 10 nm. The inert and high hardness Al2O3layer is expected to lower the polarization and restrain the growth of Zn dendrites. Atomic force microscopy was employed to evaluate the roughness of the surface of the deposited Zn and Al2O3/Zn anode structures. Long-term cycling stability was gauged under the symmetrical cells at 0.5 mA cm-2for 1 mAh cm-2. Then the fabricated Zn anode was paired with MnO2as a full cell for further electrochemical performance testing. To investigate the evolution of the interface between the Zn anode and the electrolyte, a home-developed in-situ optical observation battery cage was employed to record and compare the process of Zn deposition on the anodes of the Al2O3/Zn (demonstrated in this study) and the procured thick Zn anode. The surface morphology of the two Zn anodes after circulation was characterized and compared through scanning electron microscopy. The tunable ultrathin Zn metal anode with enhanced anode stability provides a pathway for future high-energy-density Zn-ion batteries.
Obama, B., The irreversible momentum of clean energy.
Science 2017, 355 (6321), 126-129.Goodenough, J. B.; Park, K. S., The Li-ion rechargeable battery: a perspective.
J Am Chem Soc 2013, 135 (4), 1167-76.Li, C.; Xie, X.; Liang, S.; Zhou, J., Issues and Future Perspective on Zinc Metal Anode for Rechargeable Aqueous Zinc‐ion Batteries.
Energy & Environmental Materials 2020, 3 (2), 146-159.Jia, H.; Wang, Z.; Tawiah, B.; Wang, Y.; Chan, C.-Y.; Fei, B.; Pan, F., Recent advances in zinc anodes for high-performance aqueous Zn-ion batteries.
Nano Energy 2020, 70 .Yang, J.; Yin, B.; Sun, Y.; Pan, H.; Sun, W.; Jia, B.; Zhang, S.; Ma, T., Zinc Anode for Mild Aqueous Zinc-Ion Batteries: Challenges, Strategies, and Perspectives.
Nanomicro Lett 2022, 14 (1), 42.Yang, Q.; Li, Q.; Liu, Z.; Wang, D.; Guo, Y.; Li, X.; Tang, Y.; Li, H.; Dong, B.; Zhi, C., Dendrites in Zn-Based Batteries.
Adv Mater 2020, 32 (48), e2001854.Acknowledgment
This work was partially supported by the U.S. National Science Foundation (NSF) Award No. ECCS-1931088. S.L. and H.W.S. acknowledge the support from the Improvement of Measurement Standards and Technology for Mechanical Metrology (Grant No. 22011044) by KRISS.
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null (Ed.)Single crystals of two new germanates, [(Rb 6 F)(Rb 4 F)][Ge 14 O 32 ] and [(Rb 6 F)(Rb 3.1 Co 0.9 F 0.96 )][Co 3.8 Ge 10.2 O 30 F 2 ], were synthesized via high temperature RbCl/RbF flux growth. Both compounds crystallize in the cubic space group F 4̄3 m and possess the germanium framework of the previously reported salt inclusion material (SIM), [(Cs 6 F)(Cs 3 AgF)][Ge 14 O 32 ], related to the Ge 7 O 16 zeolitic family. These materials demonstrate the ability to accommodate a variety of salt-inclusions, and exhibit chemical flexibility enabling modifications of the framework through incorporation of Co. Alteration of the salt-inclusion led to intrinsic luminescence of [(Rb 6 F)(Rb 4 F)][Ge 14 O 32 ] while modification of the framework resulted in an unanticipated Rb/Co salt/inclusion in [(Rb 6 F)(Rb 3.1 Co 0.9 F 0.96 )][Co 3.8 Ge 10.2 O 30 F 2 ]. Fluorescence measurements were performed on [(Rb 6 F)(Rb 4 F)][Ge 14 O 32 ]. First-principles calculations in the form of density functional theory (DFT) were performed for [(Rb 6 F)(Rb 3.1 Co 0.9 F 0.96 )][Co 3.8 Ge 10.2 O 30 F 2 ] to elucidate its electronic and magnetic properties, and stability at 0 K.more » « less
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Abstract One-dimensional c -axis-aligned BaZrO 3 (BZO) nanorods are regarded as strong one-dimensional artificial pinning centers (1D-APCs) in BZO-doped YaBa 2 Cu 3 O 7− x (BZO/YBCO) nanocomposite films. However, a microstructure analysis has revealed a defective, oxygen-deficient YBCO column around the BZO 1D-APCs due to the large lattice mismatch of ∼7.7% between the BZO (3a = 1.26 nm) and YBCO (c = 1.17 nm), which has been blamed for the reduced pinning efficiency of BZO 1D-APCs. Herein, we report a dynamic lattice enlargement approach on the tensile strained YBCO lattice during the BZO 1D-APCs growth to induce c -axis elongation of the YBCO lattice up to 1.26 nm near the BZO 1D-APC/YBCO interface via Ca/Cu substitution on single Cu-O planes of YBCO, which prevents the interfacial defect formation by reducing the BZO/YBCO lattice mismatch to ∼1.4%. Specifically, this is achieved by inserting thin Ca 0.3 Y 0.7 Ba 2 Cu 3 O 7− x (CaY-123) spacers as the Ca reservoir in 2–6 vol.% BZO/YBCO nanocomposite multilayer (ML) films. A defect-free, coherent BZO 1D-APC/YBCO interface is confirmed in transmission electron microscopy and elemental distribution analyses. Excitingly, up to five-fold enhancement of J c ( B ) at magnetic field B = 9.0 T// c -axis and 65 K–77 K was obtained in the ML samples as compared to their BZO/YBCO single-layer (SL) counterpart’s. This has led to a record high pinning force density F p together with significantly enhanced B max at which F p reaches its maximum value F p,max for BZO 1D-APCs at B // c -axis. At 65 K, the F p,max ∼158 GN m −3 and B max ∼ 8.0 T for the 6% BZO/YBCO ML samples represent a significant enhancement over F p,max ∼ 36.1 GN m −3 and B max ∼ 5.0 T for the 6% BZO/YBCO SL counterparts. This result not only illustrates the critical importance of a coherent BZO 1D-APC/YBCO interface in the pinning efficiency, but also provides a facile scheme to achieve such an interface to restore the pristine pinning efficiency of the BZO 1D-APCs.more » « less
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We report results of the optical properties of Dy-doped CsPbCl3and KPb2Cl5bulk crystals for potential applications in yellow solid-state laser development. The crystals were synthesized from purified starting materials and melt-grown by vertical Bridgman technique. Optical transmission measurements revealed characteristic absorption bands from intra-4f transitions of Dy3+ions. Direct optical excitation at 455 nm (6H15/2→4I15/2) resulted in dominant yellow emission bands at ∼575 nm from the4F9/2excited state of Dy3+ions. In addition, both crystals exhibited weaker emission lines in the blue (∼483 nm) and red (∼670 nm) regions. The peak emission-cross sections for the yellow transition (4F9/2→6H13/2) were determined to be ∼0.22 × 10−20cm2for Dy: CsPbCl3(λpeak = 576.5 nm) and ∼0.59 × 10−20cm2for Dy: KPb2Cl5(λpeak = 574.5 nm). The spectral properties and decay dynamics of the4F9/2excited state were evaluated within the Judd-Ofelt theory to predict total radiative decay rates, branching ratios, and emission quantum efficiencies.
