The performance of asymmetric supercapacitors(ASCs)is strongly restricted by the capacity gap between the positive and negative electrodes.To address this issue,two new electrode materials deriving from Co‐and Fe‐ba...The performance of asymmetric supercapacitors(ASCs)is strongly restricted by the capacity gap between the positive and negative electrodes.To address this issue,two new electrode materials deriving from Co‐and Fe‐based metal–organic frameworks(MOFs,Co‐TAMBA‐d,and Fe‐TAMBA‐d)through a single‐step sintering method have been developed by considering the superiorities of the derivatives of MOFs including large surface areas,sufficient metal‐atom‐doping content,and extreme surface wettability to the bath solution.The as‐prepared Co‐TAMBA‐d as a positive electrode delivers typical pseudocapacitive behavior with the improvement of capacity,which is better than those of pristine MOF materials,while Fe‐TAMBA‐d as negative electrodes displays better electrochemical behavior than those of activated carbon.ASCs based on these two electrodes exhibits excellent energy density and power density of 47Wh/kg and 1658 W/kg,respectively,where this device can maintain prominent cycling stability with capacity retention after 5000 cycles being about 75%.Furthermore,the capacity can feed a series of red light‐emitting diodes,which gives solid evidence of the potential utilization.These results can afford the feasibility of isostructural MOF derivatives as promising electrodes in novel ASCs.展开更多
Two co-crystalline compounds containing telluric acid and iodate,namely AIO_(3)·H_(6)TeO_(6)(A=Rb^(+),NH_(4)^(+)),were investigated as potential nonlinear optical materials.They crystallize into isostructural and...Two co-crystalline compounds containing telluric acid and iodate,namely AIO_(3)·H_(6)TeO_(6)(A=Rb^(+),NH_(4)^(+)),were investigated as potential nonlinear optical materials.They crystallize into isostructural and consist of isolated[IO_(3)]group and[H_(6)TeO_(6)]molecule linked by hydrogen bonds and charge interactions of Rb^(+)/NH_(4)^(+).They show phase-matching second harmonic generation responses with moderate intensity of 1.2×KDP(Rb^(+))and 1.1×KDP(NH_(4)^(+)).They also possess large optical band gaps over 4.25 eV and can be easily grown from aqueous so-lutions.The local dipole moment calculations based on the structures of AIO_(3)·H_(6)TeO_(6)(A=K+,Rb^(+),NH_(4)^(+))series of compounds indicate that the change of A+cation in their structural frame causes a slight change in the arrangement directions of[IO_(3)]and[Te(OH)_(6)]groups,and further induces their SHG responses of different in-tensities at the macroscopic level.展开更多
Isostructural multicomponent crystals provide a promising way for fine-tuning physicochemical properties, whereas their design remains quite challenging. The purpose of this work was to provide a new strategy for obta...Isostructural multicomponent crystals provide a promising way for fine-tuning physicochemical properties, whereas their design remains quite challenging. The purpose of this work was to provide a new strategy for obtaining isostructural multicomponent crystals by introducing coformers with functional group positional isomerism. Five isostructural salts of an antitumor drug dimethylaminomicheliolide(DMAMCL) were reported and designed with a series of dihydroxybenzoic acid regioisomers for the first time, which were identified by power and single-crystal X-ray diffractions. Similar lattice parameters suggested these obtained salts may have the same crystal packing mode. The quantitative similarity parameters via XPac, Crystal CMP and Mercury program further proved these crystal structures are3D isostructural. Hirshfeld surface maps and 2D fingerprint plots show that the isostructural salts have similar intermolecular interactions. Compared with DMAMCL, obvious improvement was observed in the thermal stability, hygroscopicity, and solubility of these isostructural salts. Meanwhile, isostructural crystals may have different physicochemical properties, even though the shape and molecular size are similar and the packing of crystal structures is equally matched.展开更多
Two novel 3-D coordination compounds, Nd2[C6（COO）6]（H2O）6 （1）and Ho2[C6（COO）6]（H2O）6 （2）, were hydrothermaily synthesized from mellitic acid and neodymium perchlorate （or holmium perchlorate） in the alka...Two novel 3-D coordination compounds, Nd2[C6（COO）6]（H2O）6 （1）and Ho2[C6（COO）6]（H2O）6 （2）, were hydrothermaily synthesized from mellitic acid and neodymium perchlorate （or holmium perchlorate） in the alkaline aqueous solution and characterized with elemental analysis, TG, IR spectrum, and single crystal X-ray diffraction. The two compounds were isostructural and crystallized in the orthorhombic system, space group Pnnm, with a=1.3531 （4） nm, b=0.6687 （2） nm, c=1.0224（3） nm, V=0.92523（5） nm^3, Z=4, D=2.630 g/cm^3, F（000）=696.0, Goof=1.052. Final R indices [1 〉2∑（Ⅰ）]： R1=0.0195, wR2=0.0382 for 1; a=1.3411 （2） nm, b=0.6586（1） nm, c=1.0116（2） nm, V=0.8935（3） nm^3, Z=4, D=2.877 g/cm^3, F（000）=724.0, Goof=1.061. Final R indices [1 〉2∑（Ⅰ）]： R1=0.0200, wR2=0.0479 for 2. In the two compounds 1 and 2, the mellitic acid ligand, in which all the carboxylate groups were deprotonated, had only one kind of coordination mode to bridge metal ions to form four-connected three-dimensional diamondiod networks.展开更多
All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,...All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,complicating their optimization and limiting the understanding of their enhanced performance.Here,the underlying structure-property correlation is explored by using a well-defined cobalt-phosphate polyoxometalate cluster [{(Co4)(OH)3(PO4)}4(SiW9 O34)4]^32-(1),which may serve as a molecular model of multimetal hydr(oxy)oxides.The catalytic activity is enhanced upon replacing Co by Fe in 1,resulting in a reduced overpotential(385 mV) for oxygen evolution(by 66 mV) compared to that of the parent 1 at 10 mA cm^-2 in an acidic medium;this overpotential is comparable to that for the IrO2 catalyst These abundant-metal-based polyoxometalates exhibit high stability,with no evidence of degradation even after 24 h of operation.展开更多
High pressure structural phase transition of monoclinic paraotwayite type α-Ni(OH)2 nanowires with a diameter of15 nm–20 nm and a length of several micrometers were studied by synchrotron x-ray diffraction(XRD) and ...High pressure structural phase transition of monoclinic paraotwayite type α-Ni(OH)2 nanowires with a diameter of15 nm–20 nm and a length of several micrometers were studied by synchrotron x-ray diffraction(XRD) and Raman spectra.It is found that the α-Ni(OH)2 nanowires experience an isostructural phase transition associated with the amorphization of the H-sublattice of hydroxide in the interlayer spaces of the two-dimensional crystal structure at 6.3 GPa–9.3 GPa. We suggest that the isostructural phase transition can be attributed to the amorphization of the H-sublattice. The bulk moduli for the low pressure phase and the high pressure phase are 41.2(4.2) GPa and 94.4(5.6) GPa, respectively. Both the pressure-induced isostructural phase transition and the amorphization of the H-sublattice in the α-Ni(OH)2 nanowires are reversible upon decompression. Our results show that the foreign anions intercalated between the α-Ni(OH)2 layers play important roles in their structural phase transition.展开更多
The relation between cell-edges or unit-cell volumes of isostructural compounds and theionic radii has wide applications in crystal chemistry. The authors have proved: (1) For a series of multiple isostructural compou...The relation between cell-edges or unit-cell volumes of isostructural compounds and theionic radii has wide applications in crystal chemistry. The authors have proved: (1) For a series of multiple isostructural compounds such as A_mB_n…X_p, when the anionand other cations are fixed, there exists the following relation between the unit-cell volume Vand the radius r_A of a certain cation such as A: V = (a + br_A)(r_X + r_A)~3 (a and b are constants). (2) For binary isostructural compounds A_mX_p, the above relation is reduced to V = k(r_X + r_A)~3 (k is a constant). (3) For binary isostructural compounds the relation between V and r_A^3 is approximatelylinear, and for multiple compounds, it is often curvilinear but still approximately linear whenthe variation of r_A is slight. As another approximation, a linear relation also exists betweenV and r_A for isostructural compounds. (4) The relation of ce1l-edge a vs. r_A is linear for binary isostructural compounds. Butno such a good linear relation exists for multiple isostructural compounds.展开更多
Triboelectric nanogenerator(TENG)can directly convert mechanical energy into electric energy.However,the triboelectric materials are limited to the triboelectric series.Here,for the first time,we choose the isostructu...Triboelectric nanogenerator(TENG)can directly convert mechanical energy into electric energy.However,the triboelectric materials are limited to the triboelectric series.Here,for the first time,we choose the isostructural UiO-66-X(X=H,NH_(2),NO_(2),and Br)family as triboelectric materials to investigate the underlying relationships between different functional groups and the triboelectric performance of TENG.Unlike traditional triboelectric material organic polymers,metal–organic frameworks(MOFs)can be oriented design synthesis and functionalized with various functional groups.The results demonstrate that the largest output voltage and current are from UiO-66-NO_(2) TENG,and are about 23.79 V and 0.29μA,which are 3.19 and 4.14 times over that of the UiO-66 TENG,respectively.The working mechanism of the MOF TENG was discussed in depth through experiments and theoretical calculations.This work proves a novel strategy to obtain high output properties by functionalized MOFs with large electron-withdrawing functional groups and promising guidance for the choice of high-efficiency triboelectric materials.展开更多
The high-pressure structural,vibrational and electrical properties for realgar were investigated by in-situ Raman scattering and electrical conductivity experiments combined with first-principle calculations up to~30....The high-pressure structural,vibrational and electrical properties for realgar were investigated by in-situ Raman scattering and electrical conductivity experiments combined with first-principle calculations up to~30.8 GPa.It was verified that realgar underwent an isostructural phase transition at~6.3 GPa and a metallization at a higher pressure of~23.5 GPa.The isostructural phase transition was well evidenced by the obvious variations of Raman peaks,electrical conductivity,crystal parameters and the As–S bond length.The phase transition of metallization was in closely associated with the closure of bandgap rather than caused by the structural phase transition.And furthermore,the metallic realgar exhibited a relatively low compressibility with the unit cell volume V_(0)=718.1.4Å^(3)and bulk modulus B_(0)=36.1 GPa.展开更多
SiO_(2)is the major mineral substance in the upper mantle of the earth.Therefore,studies of the silica-coated materials under high-pressure are essential to explore the physical and chemical properties of the upper ma...SiO_(2)is the major mineral substance in the upper mantle of the earth.Therefore,studies of the silica-coated materials under high-pressure are essential to explore the physical and chemical properties of the upper mantle.The silica-confined CsPbBr_(3)nanocrystals(NCs)have recently attracted much attention because of the improved photoluminescence(PL)quantum yield,owing to the protection of silica shell.However,it remains considerable interest to further explore the relationship between optical properties and the structure of CsPbBr_(3)@SiO_(2)NCs.We systemically studied the structural and optical properties of the CsPbBr_(3)@SiO_(2)NCs under high pressure by using diamond anvil cell(DAC).The discontinuous changes of PL and absorption spectra occurred at~1.40 GPa.Synchrotron X-ray diffraction(XRD)studies of CsPbBr_(3)@SiO_(2)NCs under high pressure indicated an isostructural phase transformation at about 1.36 GPa,owing to the pressure-induced tilting of the Pb-Br octahedra.The isothermal bulk moduli for two phases are estimated about 60.0 GPa and 19.2 GPa by fitting the equation of state.Besides,the transition pressure point of CsPbBr_(3)@SiO_(2)NCs is slightly higher than that of pristine CsPbBr_(3)NCs,which attributed to the buffer effect of coating silica shell.The results indicate that silica shell is able to enhance the stabilization without changing the relationship between optical properties and structure of CsPbBr_(3)NCs.Our results were fascinated to model the rock metasomatism in the upper mantle and provided a new‘lithoprobe’for detecting the upper mantle.展开更多
Three new isostructural coordination polymers,namely,[Mg(cpna)(H2O)2]n(1),[Mn(cpna)(H_(2)O)_(2)]n(2)and[Co(cpna)(H_(2)O)_(2)]n(3)(H_(2) cpna=5-(3-carboxylphenyl)nicotic acid)are reported.They were synthesized by hydro...Three new isostructural coordination polymers,namely,[Mg(cpna)(H2O)2]n(1),[Mn(cpna)(H_(2)O)_(2)]n(2)and[Co(cpna)(H_(2)O)_(2)]n(3)(H_(2) cpna=5-(3-carboxylphenyl)nicotic acid)are reported.They were synthesized by hydrothermal reactions of transition metal or alkaline earth metal chloride with 5-(3-carboxylphenyl)nicotic acid,respectively.Complexes 1~3 exhibit 2D layers with a 3,3-connected topology with Schl?fli symbol{4.82}.Such layers including hexagonal rings and a quadrangular ring are further extended into an ordered 3D framework by hydrogen bonds between the cpna2-ligands and water molecules.The rare complex 1 has excellent luminescence and can be used as luminescent materials,while 2 and 3 possess prominent magnetism with potential applications in magnetic materials.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:22279061,21901120,21371098The Fundamental Research Funds for the Central Universities,the Natural Science Foundation of Jiangsu Province,Grant/Award Numbers:BK20180514,BK20190503,BK20131314+1 种基金The Qing Lan Project of Jiangsu Province.Q.Z.thanks the funding support from City University of Hong Kong,Grant/Award Numbers:9380117,7005620 and 7020040Hong Kong Institute for Advanced Study,City University of Hong Kong,China。
文摘The performance of asymmetric supercapacitors(ASCs)is strongly restricted by the capacity gap between the positive and negative electrodes.To address this issue,two new electrode materials deriving from Co‐and Fe‐based metal–organic frameworks(MOFs,Co‐TAMBA‐d,and Fe‐TAMBA‐d)through a single‐step sintering method have been developed by considering the superiorities of the derivatives of MOFs including large surface areas,sufficient metal‐atom‐doping content,and extreme surface wettability to the bath solution.The as‐prepared Co‐TAMBA‐d as a positive electrode delivers typical pseudocapacitive behavior with the improvement of capacity,which is better than those of pristine MOF materials,while Fe‐TAMBA‐d as negative electrodes displays better electrochemical behavior than those of activated carbon.ASCs based on these two electrodes exhibits excellent energy density and power density of 47Wh/kg and 1658 W/kg,respectively,where this device can maintain prominent cycling stability with capacity retention after 5000 cycles being about 75%.Furthermore,the capacity can feed a series of red light‐emitting diodes,which gives solid evidence of the potential utilization.These results can afford the feasibility of isostructural MOF derivatives as promising electrodes in novel ASCs.
基金support from the National Natural Science Foundation of China(Grant No.22105046)the Natural Science Foundation of Guangxi Province(No.2022GXNSFBA035484)the Shanghai Pujiang Program(20PJ1412900).
文摘Two co-crystalline compounds containing telluric acid and iodate,namely AIO_(3)·H_(6)TeO_(6)(A=Rb^(+),NH_(4)^(+)),were investigated as potential nonlinear optical materials.They crystallize into isostructural and consist of isolated[IO_(3)]group and[H_(6)TeO_(6)]molecule linked by hydrogen bonds and charge interactions of Rb^(+)/NH_(4)^(+).They show phase-matching second harmonic generation responses with moderate intensity of 1.2×KDP(Rb^(+))and 1.1×KDP(NH_(4)^(+)).They also possess large optical band gaps over 4.25 eV and can be easily grown from aqueous so-lutions.The local dipole moment calculations based on the structures of AIO_(3)·H_(6)TeO_(6)(A=K+,Rb^(+),NH_(4)^(+))series of compounds indicate that the change of A+cation in their structural frame causes a slight change in the arrangement directions of[IO_(3)]and[Te(OH)_(6)]groups,and further induces their SHG responses of different in-tensities at the macroscopic level.
基金financially supported by the Key R&D Project of Hebei Province (No. 21282602Z)Shandong Province (No. 2020CXGC010506)the Innovative Group Project (No. 21621004)。
文摘Isostructural multicomponent crystals provide a promising way for fine-tuning physicochemical properties, whereas their design remains quite challenging. The purpose of this work was to provide a new strategy for obtaining isostructural multicomponent crystals by introducing coformers with functional group positional isomerism. Five isostructural salts of an antitumor drug dimethylaminomicheliolide(DMAMCL) were reported and designed with a series of dihydroxybenzoic acid regioisomers for the first time, which were identified by power and single-crystal X-ray diffractions. Similar lattice parameters suggested these obtained salts may have the same crystal packing mode. The quantitative similarity parameters via XPac, Crystal CMP and Mercury program further proved these crystal structures are3D isostructural. Hirshfeld surface maps and 2D fingerprint plots show that the isostructural salts have similar intermolecular interactions. Compared with DMAMCL, obvious improvement was observed in the thermal stability, hygroscopicity, and solubility of these isostructural salts. Meanwhile, isostructural crystals may have different physicochemical properties, even though the shape and molecular size are similar and the packing of crystal structures is equally matched.
基金supported by the Nature Science Foundation of Guangdong Province (7005808)Guangdong Provincial Science and Technology Bureau (2008B010600009)the National Natural Science Foundation of China (U0734005)
文摘Two novel 3-D coordination compounds, Nd2[C6（COO）6]（H2O）6 （1）and Ho2[C6（COO）6]（H2O）6 （2）, were hydrothermaily synthesized from mellitic acid and neodymium perchlorate （or holmium perchlorate） in the alkaline aqueous solution and characterized with elemental analysis, TG, IR spectrum, and single crystal X-ray diffraction. The two compounds were isostructural and crystallized in the orthorhombic system, space group Pnnm, with a=1.3531 （4） nm, b=0.6687 （2） nm, c=1.0224（3） nm, V=0.92523（5） nm^3, Z=4, D=2.630 g/cm^3, F（000）=696.0, Goof=1.052. Final R indices [1 〉2∑（Ⅰ）]： R1=0.0195, wR2=0.0382 for 1; a=1.3411 （2） nm, b=0.6586（1） nm, c=1.0116（2） nm, V=0.8935（3） nm^3, Z=4, D=2.877 g/cm^3, F（000）=724.0, Goof=1.061. Final R indices [1 〉2∑（Ⅰ）]： R1=0.0200, wR2=0.0479 for 2. In the two compounds 1 and 2, the mellitic acid ligand, in which all the carboxylate groups were deprotonated, had only one kind of coordination mode to bridge metal ions to form four-connected three-dimensional diamondiod networks.
文摘All-inorganic and earth-abundant bi-/trimetallic hydr(oxy)oxides are widely used as oxygen evolution electrocatalysts owing to their remarkable performance.However,their atomically precise structures remain undefined,complicating their optimization and limiting the understanding of their enhanced performance.Here,the underlying structure-property correlation is explored by using a well-defined cobalt-phosphate polyoxometalate cluster [{(Co4)(OH)3(PO4)}4(SiW9 O34)4]^32-(1),which may serve as a molecular model of multimetal hydr(oxy)oxides.The catalytic activity is enhanced upon replacing Co by Fe in 1,resulting in a reduced overpotential(385 mV) for oxygen evolution(by 66 mV) compared to that of the parent 1 at 10 mA cm^-2 in an acidic medium;this overpotential is comparable to that for the IrO2 catalyst These abundant-metal-based polyoxometalates exhibit high stability,with no evidence of degradation even after 24 h of operation.
基金Project supported by the National Key Research and Development Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant Nos.11874172,11374120,11634004,and 51320105007)the Fund from Jilin University for Science and Technology Innovative Research Team(Grant No.2017TD-01)
文摘High pressure structural phase transition of monoclinic paraotwayite type α-Ni(OH)2 nanowires with a diameter of15 nm–20 nm and a length of several micrometers were studied by synchrotron x-ray diffraction(XRD) and Raman spectra.It is found that the α-Ni(OH)2 nanowires experience an isostructural phase transition associated with the amorphization of the H-sublattice of hydroxide in the interlayer spaces of the two-dimensional crystal structure at 6.3 GPa–9.3 GPa. We suggest that the isostructural phase transition can be attributed to the amorphization of the H-sublattice. The bulk moduli for the low pressure phase and the high pressure phase are 41.2(4.2) GPa and 94.4(5.6) GPa, respectively. Both the pressure-induced isostructural phase transition and the amorphization of the H-sublattice in the α-Ni(OH)2 nanowires are reversible upon decompression. Our results show that the foreign anions intercalated between the α-Ni(OH)2 layers play important roles in their structural phase transition.
文摘The relation between cell-edges or unit-cell volumes of isostructural compounds and theionic radii has wide applications in crystal chemistry. The authors have proved: (1) For a series of multiple isostructural compounds such as A_mB_n…X_p, when the anionand other cations are fixed, there exists the following relation between the unit-cell volume Vand the radius r_A of a certain cation such as A: V = (a + br_A)(r_X + r_A)~3 (a and b are constants). (2) For binary isostructural compounds A_mX_p, the above relation is reduced to V = k(r_X + r_A)~3 (k is a constant). (3) For binary isostructural compounds the relation between V and r_A^3 is approximatelylinear, and for multiple compounds, it is often curvilinear but still approximately linear whenthe variation of r_A is slight. As another approximation, a linear relation also exists betweenV and r_A for isostructural compounds. (4) The relation of ce1l-edge a vs. r_A is linear for binary isostructural compounds. Butno such a good linear relation exists for multiple isostructural compounds.
基金supported by National Natural Science Foundation of China(No.21905255)Natural Science Foundation of Shanxi Province(No.201901D211219).
文摘Triboelectric nanogenerator(TENG)can directly convert mechanical energy into electric energy.However,the triboelectric materials are limited to the triboelectric series.Here,for the first time,we choose the isostructural UiO-66-X(X=H,NH_(2),NO_(2),and Br)family as triboelectric materials to investigate the underlying relationships between different functional groups and the triboelectric performance of TENG.Unlike traditional triboelectric material organic polymers,metal–organic frameworks(MOFs)can be oriented design synthesis and functionalized with various functional groups.The results demonstrate that the largest output voltage and current are from UiO-66-NO_(2) TENG,and are about 23.79 V and 0.29μA,which are 3.19 and 4.14 times over that of the UiO-66 TENG,respectively.The working mechanism of the MOF TENG was discussed in depth through experiments and theoretical calculations.This work proves a novel strategy to obtain high output properties by functionalized MOFs with large electron-withdrawing functional groups and promising guidance for the choice of high-efficiency triboelectric materials.
基金the strategic priority Research Program(B)of the Chinese Academy of Sciences(Grant No.18010401)Key Research Program of Frontier Sciences of CAS(Grant No.QYZDB-SSW-DQC009)+3 种基金Hundred Talents Program of CAS,NSF of China(Grant Nos.41774099 and 41772042)Youth Innovation Promotion Association of CAS(Grant No.2019390)Special Fund of the West Light Foundation of CASthe Supercomputer Center of Fujian Institute of Research on the Structure of Matter(FJIRSM)is acknowledged.
文摘The high-pressure structural,vibrational and electrical properties for realgar were investigated by in-situ Raman scattering and electrical conductivity experiments combined with first-principle calculations up to~30.8 GPa.It was verified that realgar underwent an isostructural phase transition at~6.3 GPa and a metallization at a higher pressure of~23.5 GPa.The isostructural phase transition was well evidenced by the obvious variations of Raman peaks,electrical conductivity,crystal parameters and the As–S bond length.The phase transition of metallization was in closely associated with the closure of bandgap rather than caused by the structural phase transition.And furthermore,the metallic realgar exhibited a relatively low compressibility with the unit cell volume V_(0)=718.1.4Å^(3)and bulk modulus B_(0)=36.1 GPa.
基金the National Science Foundation of China(Grant Nos.21725304,11774125,and 21673100)the Chang Jiang Scholars Program of China(Grant No.T2016051)+3 种基金Changbai Mountain Scholars Program(Grant No.2013007)National Defense Science and Technology Key Laboratory Fund(Grant No.6142A0306010917)Jilin Provincial Science&Technology Development Program(Grant No.20190103044JH)Scientific Research Planning Project of the Education Department of Jilin Province(Grant No.JJKH20180118KJ)。
文摘SiO_(2)is the major mineral substance in the upper mantle of the earth.Therefore,studies of the silica-coated materials under high-pressure are essential to explore the physical and chemical properties of the upper mantle.The silica-confined CsPbBr_(3)nanocrystals(NCs)have recently attracted much attention because of the improved photoluminescence(PL)quantum yield,owing to the protection of silica shell.However,it remains considerable interest to further explore the relationship between optical properties and the structure of CsPbBr_(3)@SiO_(2)NCs.We systemically studied the structural and optical properties of the CsPbBr_(3)@SiO_(2)NCs under high pressure by using diamond anvil cell(DAC).The discontinuous changes of PL and absorption spectra occurred at~1.40 GPa.Synchrotron X-ray diffraction(XRD)studies of CsPbBr_(3)@SiO_(2)NCs under high pressure indicated an isostructural phase transformation at about 1.36 GPa,owing to the pressure-induced tilting of the Pb-Br octahedra.The isothermal bulk moduli for two phases are estimated about 60.0 GPa and 19.2 GPa by fitting the equation of state.Besides,the transition pressure point of CsPbBr_(3)@SiO_(2)NCs is slightly higher than that of pristine CsPbBr_(3)NCs,which attributed to the buffer effect of coating silica shell.The results indicate that silica shell is able to enhance the stabilization without changing the relationship between optical properties and structure of CsPbBr_(3)NCs.Our results were fascinated to model the rock metasomatism in the upper mantle and provided a new‘lithoprobe’for detecting the upper mantle.
基金supported by the National Natural Science Foundation of China(21703247)the Science Foundation of Fujian Province(2018J05029,2019J05156,2019H0053)。
文摘Three new isostructural coordination polymers,namely,[Mg(cpna)(H2O)2]n(1),[Mn(cpna)(H_(2)O)_(2)]n(2)and[Co(cpna)(H_(2)O)_(2)]n(3)(H_(2) cpna=5-(3-carboxylphenyl)nicotic acid)are reported.They were synthesized by hydrothermal reactions of transition metal or alkaline earth metal chloride with 5-(3-carboxylphenyl)nicotic acid,respectively.Complexes 1~3 exhibit 2D layers with a 3,3-connected topology with Schl?fli symbol{4.82}.Such layers including hexagonal rings and a quadrangular ring are further extended into an ordered 3D framework by hydrogen bonds between the cpna2-ligands and water molecules.The rare complex 1 has excellent luminescence and can be used as luminescent materials,while 2 and 3 possess prominent magnetism with potential applications in magnetic materials.
