Improving the optoelectronic behavior and stress-deformation stability of conjugated materials is crucial for the realization of their potential applications in flexible optoelectronics.To tune the emission behavior a...Improving the optoelectronic behavior and stress-deformation stability of conjugated materials is crucial for the realization of their potential applications in flexible optoelectronics.To tune the emission behavior and mechanical property of molecular crystals simultaneously via supramolecular salt strategy is rarely reported,which is very important to improve their photophysical behavior and softness for the fabrication of flexible light-emitting device.Herein,supramolecular salt approach has been successfully applied to synthesize two elastic organic fluorescent crystals(CMOH-Py-Cl and CMOH-Py-Br)derived from non-emissive and brittle pyridine-substituted coumarin derivative(CMOH-Py).Their elastic properties can be attributed to the prevalent presence of numerous weak interactions introduced by halogen atoms,which are beneficial to the absorption and release of mechanical energy.Furthermore,density functional theory(DFT)calculations demonstrated a narrowing of the HOMO-LUMO energy gaps from CMOH-Py to CMOH-Py-Cl/CMOH-Py-Br via supramolecular salt approach.Finally,the application of flexible crystal materials in the field of optical waveguides has been investigated.The transformation of crystals in terms of photophysical and mechanical properties,achieved by the supramolecular salt approach,offers novel insights into the design and construction of flexible crystalline materials,providing a new path for the development of next-generation smart materials.展开更多
为了解决连续谱中束缚态空间响应带宽偏小的技术难题,本文设计了一种简单的光子晶体平板,并进行能带的计算和模式Q因子分析.通过结构参数的优化,在k空间发现一种正方形环状的且边长可调节的准连续谱中束缚态(bound state in the continu...为了解决连续谱中束缚态空间响应带宽偏小的技术难题,本文设计了一种简单的光子晶体平板,并进行能带的计算和模式Q因子分析.通过结构参数的优化,在k空间发现一种正方形环状的且边长可调节的准连续谱中束缚态(bound state in the continuum, BIC)分布.分析准BIC环与等频线的关系以及模场分布的特征发现,这种正方形环状的准BIC来自结构的全内反射和驻波干涉效应.分别通过入射角度和频率扫描计算结构的透射谱,得到了高Q因子的法诺共振谱线,进而验证了环状准BIC的存在.展开更多
Exploring new material systems and enhancing the birefringence of compounds is a highly valuable endeavor.In this study,we introduce a novel method to enhance the birefringence of inorganic compounds by inducing struc...Exploring new material systems and enhancing the birefringence of compounds is a highly valuable endeavor.In this study,we introduce a novel method to enhance the birefringence of inorganic compounds by inducing structural alignment through linear groups and fluoride ions.We report on two new compounds:HgGa_(2)(SeO_(3))_(4) and Hg_(2)Ga(Se_(O)_(3))_(2)F.HgGa_(2)(SeO_(3))_(4) crystallizes in a non-centrosymmetric(NCS)space group,exhibiting a second harmonic generation(SHG)efficiency of approximately 60% that of commercial KH2PO4(KDP),with a birefringence of 0.032@546 nm.Hg_(2)Ga(Se_(O)_(3))_(2)F,on the other hand,crystallizes in a centrosymmetric space(CS)group and represents the first reported HgI-based selenite birefringent material.Due to the influence of the linear group Hg_(2)O_(2),its birefringence is significantly enhanced to 0.111@546 nm,which is 3.5 times that of HgGa_(2)(SeO_(3))_(4).Moreover,both compounds demonstrate high stability and a broad optical transparency window.These findings indicate that Hg_(2)Ga(Se_(O)_(3))_(2)F is a promising candidate for birefringent material in the mid-infrared(MIR)range.Our research provides an innovative strategy for improving the birefringence of compounds.展开更多
Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_...Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_(2)O_(4)=oxalic acid,C_(6)N_(2)H_(11)=2-ethyl-4-methylimidazolium cation and C_(4)N_(2)H_(4)=pyrazine).Remarkably,crystal 2 exhibits an unprecedentedly large birefringence of 0.422 at 550 nm,which surpasses all commercial birefringent crystals.The formation of the directional hydrogen bonds between oxalate and planar pyrazine constituents facilitates the adoption of a planar configuration by oxalic units possessing large polarizability anisotropy(Δα=21.72).Whereas the distorted configuration of oxalate groups with a relatively small Δα of 13.95 induced by the non-coplanar arrangement of the imidazole planes of C_(6)N_(2)H_(11) leads to moderate birefringence(0.144@550 nm)for 1.Computational analyses reveal that the birefringent superiority of 2 originates from the synergistic effect of the π-conjugated oxalate and pyrazine units in a parallel arrangement directed by hydrogen bonds.This work breaks the record of birefringence in oxalates.It also develops a powerful hydrogen bond-directed strategy to modulate the configuration of oxalate groups,enabling its use as a tunable anisotropic structural unit for constructing birefringent crystals.展开更多
A symmetrical one-dimensional(1D)photonic crystal structure with a Dirac-emimetal-defected layer is proposed.The material properties of the Dirac semimetal are governed by three key parameters:Fermi level,Fermi veloci...A symmetrical one-dimensional(1D)photonic crystal structure with a Dirac-emimetal-defected layer is proposed.The material properties of the Dirac semimetal are governed by three key parameters:Fermi level,Fermi velocity,and degeneracy factor.Simulation results demonstrate that the proposed structure generates multiple photonic bandgaps within the THz frequency range.In the low-THz region,pronounced resonant transmission peaks emerge,enabling near-perfect filtering performance.The positions of these defect modes can be dynamically tuned by adjusting the Fermi level and degeneracy factor.In mid-and high-THz frequency bands,the Dirac semimetal begins to exhibit metallic behavior,leading to attenuation of the transmission peaks and the appearance of absorption.The elevation of the Fermi level delays the critical threshold for the transition from the dielectric state to the metallic state,while an increase in Fermi velocity suppresses metallic behavior.Therefore,enhancing both the Fermi level and Fermi velocity contributes to strengthening the defect peak intensity.Conversely,increasing the degeneracy factor strengthens the metallic characteristics,thereby disrupting the high-frequency photonic bandgap.Notably,the defect layer thickness and incident angle exert significant influence on the transmission behavior:a larger incident angle causes the defect peak to shift toward higher frequencies and reduces its intensity,whereas a thicker defect layer shifts the defect peak toward lower frequencies.The modulation effects of both parameters become more pronounced as frequency increases.Compared with conventional photonic crystals,our work can provide a tunable structure over transmission properties,offering novel strategies for designing tunable filters and optical sensors.展开更多
Achieving non-centrosymmetric(NCS) configurations in ABX3-type hybrid halides remains a critical challenge for nonlinear optical(NLO) materials due to the conflicting requirements of high second-harmonic generation(SH...Achieving non-centrosymmetric(NCS) configurations in ABX3-type hybrid halides remains a critical challenge for nonlinear optical(NLO) materials due to the conflicting requirements of high second-harmonic generation(SHG) response,wide bandgap,and phase-matching capabilities.Herein,we propose a triplesite modulation strategy by synergistically tailoring the A-site cations(2-methylimidazole cation/1-ethyl-3-methylimidazole cation),B-site metals(Sn^(2+)/Pb^(2+)),and X-site halogens(Cl/Br),which effectively disrupts lattice symmetry and enables NCS crystallization.Our results demonstrate a strong SHG response,an expanded optical bandgap and increased birefringence.The optimized compound C_(6)H_(11)N_(2)PbCl_(3) exhibits a moderately strong SHG efficiency of 3.8 × KDP,a wide bandgap(3.87 eV),and enhanced birefringence(0.139@1064 nm),surpassing majority hybrid NLO materials.The innovative anionic framework introduced here broadens the scope of hybrid NLO crystals,facilitating the integration of various aromatic heterocyclic cations.This research provides a robust strategic framework for the development of advanced NLO materials.展开更多
基金supported by the National Natural Science Foundation of China(Nos.22205105,61874053,22075136)National Key Basic Research Program of China(No.2020YFA0709900)Jiangsu Provincial Postgraduate Scientific Research Innovation Program(No.KYCX24_1649).
文摘Improving the optoelectronic behavior and stress-deformation stability of conjugated materials is crucial for the realization of their potential applications in flexible optoelectronics.To tune the emission behavior and mechanical property of molecular crystals simultaneously via supramolecular salt strategy is rarely reported,which is very important to improve their photophysical behavior and softness for the fabrication of flexible light-emitting device.Herein,supramolecular salt approach has been successfully applied to synthesize two elastic organic fluorescent crystals(CMOH-Py-Cl and CMOH-Py-Br)derived from non-emissive and brittle pyridine-substituted coumarin derivative(CMOH-Py).Their elastic properties can be attributed to the prevalent presence of numerous weak interactions introduced by halogen atoms,which are beneficial to the absorption and release of mechanical energy.Furthermore,density functional theory(DFT)calculations demonstrated a narrowing of the HOMO-LUMO energy gaps from CMOH-Py to CMOH-Py-Cl/CMOH-Py-Br via supramolecular salt approach.Finally,the application of flexible crystal materials in the field of optical waveguides has been investigated.The transformation of crystals in terms of photophysical and mechanical properties,achieved by the supramolecular salt approach,offers novel insights into the design and construction of flexible crystalline materials,providing a new path for the development of next-generation smart materials.
文摘为了解决连续谱中束缚态空间响应带宽偏小的技术难题,本文设计了一种简单的光子晶体平板,并进行能带的计算和模式Q因子分析.通过结构参数的优化,在k空间发现一种正方形环状的且边长可调节的准连续谱中束缚态(bound state in the continuum, BIC)分布.分析准BIC环与等频线的关系以及模场分布的特征发现,这种正方形环状的准BIC来自结构的全内反射和驻波干涉效应.分别通过入射角度和频率扫描计算结构的透射谱,得到了高Q因子的法诺共振谱线,进而验证了环状准BIC的存在.
基金supported by the National Natural Science Foundation of China(Nos.22475215,22031009 and 21921001)the NSF of Fujian Province(Nos.2023J01216,2024J010039)the Selfdeployment Project Research Program of Haixi Institutes,Chinese Academy of Sciences(No.CXZX-2022-GH06).
文摘Exploring new material systems and enhancing the birefringence of compounds is a highly valuable endeavor.In this study,we introduce a novel method to enhance the birefringence of inorganic compounds by inducing structural alignment through linear groups and fluoride ions.We report on two new compounds:HgGa_(2)(SeO_(3))_(4) and Hg_(2)Ga(Se_(O)_(3))_(2)F.HgGa_(2)(SeO_(3))_(4) crystallizes in a non-centrosymmetric(NCS)space group,exhibiting a second harmonic generation(SHG)efficiency of approximately 60% that of commercial KH2PO4(KDP),with a birefringence of 0.032@546 nm.Hg_(2)Ga(Se_(O)_(3))_(2)F,on the other hand,crystallizes in a centrosymmetric space(CS)group and represents the first reported HgI-based selenite birefringent material.Due to the influence of the linear group Hg_(2)O_(2),its birefringence is significantly enhanced to 0.111@546 nm,which is 3.5 times that of HgGa_(2)(SeO_(3))_(4).Moreover,both compounds demonstrate high stability and a broad optical transparency window.These findings indicate that Hg_(2)Ga(Se_(O)_(3))_(2)F is a promising candidate for birefringent material in the mid-infrared(MIR)range.Our research provides an innovative strategy for improving the birefringence of compounds.
基金supported by the National Natural Science Foundation of China(22361021,22261023)。
文摘Rational design of birefringent crystals with high birefringence remains a critical challenge.Herein we present two oxalate crystals of(C_(6)N_(2)H_(11))(HC_(2)O_(4))(1)and(C_(4)N_(2)H_(4))(H_(2)C_(2)O_(4))(2)(H_(2)C_(2)O_(4)=oxalic acid,C_(6)N_(2)H_(11)=2-ethyl-4-methylimidazolium cation and C_(4)N_(2)H_(4)=pyrazine).Remarkably,crystal 2 exhibits an unprecedentedly large birefringence of 0.422 at 550 nm,which surpasses all commercial birefringent crystals.The formation of the directional hydrogen bonds between oxalate and planar pyrazine constituents facilitates the adoption of a planar configuration by oxalic units possessing large polarizability anisotropy(Δα=21.72).Whereas the distorted configuration of oxalate groups with a relatively small Δα of 13.95 induced by the non-coplanar arrangement of the imidazole planes of C_(6)N_(2)H_(11) leads to moderate birefringence(0.144@550 nm)for 1.Computational analyses reveal that the birefringent superiority of 2 originates from the synergistic effect of the π-conjugated oxalate and pyrazine units in a parallel arrangement directed by hydrogen bonds.This work breaks the record of birefringence in oxalates.It also develops a powerful hydrogen bond-directed strategy to modulate the configuration of oxalate groups,enabling its use as a tunable anisotropic structural unit for constructing birefringent crystals.
文摘A symmetrical one-dimensional(1D)photonic crystal structure with a Dirac-emimetal-defected layer is proposed.The material properties of the Dirac semimetal are governed by three key parameters:Fermi level,Fermi velocity,and degeneracy factor.Simulation results demonstrate that the proposed structure generates multiple photonic bandgaps within the THz frequency range.In the low-THz region,pronounced resonant transmission peaks emerge,enabling near-perfect filtering performance.The positions of these defect modes can be dynamically tuned by adjusting the Fermi level and degeneracy factor.In mid-and high-THz frequency bands,the Dirac semimetal begins to exhibit metallic behavior,leading to attenuation of the transmission peaks and the appearance of absorption.The elevation of the Fermi level delays the critical threshold for the transition from the dielectric state to the metallic state,while an increase in Fermi velocity suppresses metallic behavior.Therefore,enhancing both the Fermi level and Fermi velocity contributes to strengthening the defect peak intensity.Conversely,increasing the degeneracy factor strengthens the metallic characteristics,thereby disrupting the high-frequency photonic bandgap.Notably,the defect layer thickness and incident angle exert significant influence on the transmission behavior:a larger incident angle causes the defect peak to shift toward higher frequencies and reduces its intensity,whereas a thicker defect layer shifts the defect peak toward lower frequencies.The modulation effects of both parameters become more pronounced as frequency increases.Compared with conventional photonic crystals,our work can provide a tunable structure over transmission properties,offering novel strategies for designing tunable filters and optical sensors.
基金supported by the National Natural Science Foundation of China (No.22275052)Department of Science and Technology of Hubei Province (Nos.2025AFA111 and 2024CSA076)。
文摘Achieving non-centrosymmetric(NCS) configurations in ABX3-type hybrid halides remains a critical challenge for nonlinear optical(NLO) materials due to the conflicting requirements of high second-harmonic generation(SHG) response,wide bandgap,and phase-matching capabilities.Herein,we propose a triplesite modulation strategy by synergistically tailoring the A-site cations(2-methylimidazole cation/1-ethyl-3-methylimidazole cation),B-site metals(Sn^(2+)/Pb^(2+)),and X-site halogens(Cl/Br),which effectively disrupts lattice symmetry and enables NCS crystallization.Our results demonstrate a strong SHG response,an expanded optical bandgap and increased birefringence.The optimized compound C_(6)H_(11)N_(2)PbCl_(3) exhibits a moderately strong SHG efficiency of 3.8 × KDP,a wide bandgap(3.87 eV),and enhanced birefringence(0.139@1064 nm),surpassing majority hybrid NLO materials.The innovative anionic framework introduced here broadens the scope of hybrid NLO crystals,facilitating the integration of various aromatic heterocyclic cations.This research provides a robust strategic framework for the development of advanced NLO materials.
