The Experts below are selected from a list of 222 Experts worldwide ranked by ideXlab platform
Yu Wang - One of the best experts on this subject based on the ideXlab platform.
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Stabilization of Hexazine rings in potassium polynitride at high pressure.
arXiv: Materials Science, 2020Co-Authors: Yu Wang, Maxim Bykov, Elena Bykova, Xiao Zhang, Shuqing Jiang, Eran Greenberg, Stella Chariton, Vitali B. Prakapenka, Alexander F. GoncharovAbstract:Polynitrogen molecules represent the ultimate high energy-density materials as they have a huge potential chemical energy originating from their high enthalpy. However, synthesis and storage of such compounds remain a big challenge because of difficulties to find energy efficient synthetic routes and stabilization mechanisms. Compounds of metals with nitrogen represent promising candidates for realization of energetic polynitrogen compounds, which are also environmentally benign. Here we report the synthesis of polynitrogen planar N6 Hexazine rings, stabilized in K2N6 compound, which was formed from K azide upon laser heating in a diamond anvil cell at high pressures in excess of 45 GPa and remains metastable down to 20 GPa. Synchrotron X-ray diffraction and Raman spectroscopy are used to identify this material, also exhibiting metallic luster, being all consistent with theoretically predicted structural, vibrational and electronic properties. The documented here N6 Hexazine rings represent new highly energetic polynitrogens, which have a potential for future recovery and utilization.
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Benzene-like N6 rings in a Be2N6 monolayer: a stable 2D semiconductor with high carrier mobility
Journal of Materials Chemistry C, 2017Co-Authors: Yu Wang, Zhifa Liu, Urs AeberhardAbstract:Designing new two-dimensional (2D) semiconductors with high carrier mobilities is highly desirable for material innovation, especially when the configuration has novel topological properties. Here, we proposed a first-principles-based design of a 2D crystal, namely a Be2N6 monolayer. In which, each N atom is shared by two neighboring N atoms and one Be atom, forming a novel moiety of benzene-like N6 rings. Rather than the instability of Hexazine, the Be2N6 monolayer has a moderate cohesive energy, good kinetic and thermodynamic stability, due to the stabilization effect of the Be element by forming twelve classical two-centre–two-electron (2c–2e) σ-bonds and five multicenter 6c–2e π-bonds. There are ten π electrons in a unit cell, which satisfies the Huckel rule [4n + 2] (n = 2), indicating the Be2N6 monolayer aromaticity. As a result, the Be2N6 monolayer has an ultra-high mechanical strength of up to 200 J m−2. Particle-swarm optimization (PSO) computations reveal that a cyclo-N6-containing Be2N6 monolayer is the lowest-energy configuration in 2D forms with a stoichiometry of 1 : 3, and therefore could be synthesized experimentally. Furthermore, the Be2N6 monolayer is an indirect semiconductor with a band gap of 1.71 eV at the hybrid functional level, close to that of the bulk amorphous silicon ∼1.6 eV widely used in solar cells. At this point, the high electron mobility of up to ∼104 cm2 V−1 s−1 and visible-light absorption of ∼105 cm−1 are observed for the Be2N6 monolayer. If realized, it will not only enrich the knowledge of the bonding nature of nitrogen but could also have potential applications in electronics and optoelectronics.
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Benzene-like N 6 Rings in Be 2 N 6 Monolayer: a Stable 2D Semiconductor with High Carrier Mobility
RSC, 2017Co-Authors: Li Feng, Yu Wang, Wu Hong, Liu Zhifa, Aeberhard Urs, Li YafeiAbstract:Designing new two-dimensional (2D) semiconductors with high carrier mobilities is highly desirable for material innovation, especially when the configuration has novel topological properties. Here, we proposed a first-principles-based design of a 2D crystal, namely a Be2N6 monolayer. In which, each N atom is shared by two neighboring N atoms and one Be atom, forming a novel moiety of benzene-like N6 rings. Rather than the instability of Hexazine, the Be2N6 monolayer has a moderate cohesive energy, good kinetic and thermodynamic stability, due to the stabilization effect of the Be element by forming twelve classical two-centre–two-electron (2c–2e) σ-bonds and five multicenter 6c–2e π-bonds. There are ten π electrons in a unit cell, which satisfies the Hückel rule [4n + 2] (n = 2), indicating the Be2N6 monolayer aromaticity. As a result, the Be2N6 monolayer has an ultra-high mechanical strength of up to 200 J m−2. Particle-swarm optimization (PSO) computations reveal that a cyclo-N6-containing Be2N6 monolayer is the lowest-energy configuration in 2D forms with a stoichiometry of 1 : 3, and therefore could be synthesized experimentally. Furthermore, the Be2N6 monolayer is an indirect semiconductor with a band gap of 1.71 eV at the hybrid functional level, close to that of the bulk amorphous silicon ∼1.6 eV widely used in solar cells. At this point, the high electron mobility of up to ∼104 cm2 V−1 s−1 and visible-light absorption of ∼105 cm−1 are observed for the Be2N6 monolayer. If realized, it will not only enrich the knowledge of the bonding nature of nitrogen but could also have potential applications in electronics and optoelectronics
Ivan Oleynik - One of the best experts on this subject based on the ideXlab platform.
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Novel Rubidium Poly-Nitrogen Materials at High Pressure
The Journal of chemical physics, 2017Co-Authors: Ashley S. Williams, Brad A. Steele, Ivan OleynikAbstract:First-principles crystal structure search is performed to predict novel rubidium poly-nitrogen materials at high pressure by varying the stoichiometry, i.e., relative quantities of the constituent rubidium and nitrogen atoms. Three compounds of high nitrogen content, RbN5, RbN2, and Rb4N6, are discovered. Rubidium pentazolate (RbN5) becomes thermodynamically stable at pressures above 30 GPa. The charge transfer from Rb to N atoms enables aromaticity in cyclo-N5− while increasing the ionic bonding in the crystal. Rubidium pentazolate can be synthesized by compressing rubidium azide (RbN3) and nitrogen (N2) precursors above 9.42 GPa, and its experimental discovery is aided by calculating the Raman spectrum and identifying the features attributed to N5− modes. The two other interesting compounds, RbN2 containing infinitely long single-bonded nitrogen chains and Rb4N6 consisting of single-bonded N6 Hexazine rings, become thermodynamically stable at pressures exceeding 60 GPa. In addition to the compounds with...
Urs Aeberhard - One of the best experts on this subject based on the ideXlab platform.
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Benzene-like N6 rings in a Be2N6 monolayer: a stable 2D semiconductor with high carrier mobility
Journal of Materials Chemistry C, 2017Co-Authors: Yu Wang, Zhifa Liu, Urs AeberhardAbstract:Designing new two-dimensional (2D) semiconductors with high carrier mobilities is highly desirable for material innovation, especially when the configuration has novel topological properties. Here, we proposed a first-principles-based design of a 2D crystal, namely a Be2N6 monolayer. In which, each N atom is shared by two neighboring N atoms and one Be atom, forming a novel moiety of benzene-like N6 rings. Rather than the instability of Hexazine, the Be2N6 monolayer has a moderate cohesive energy, good kinetic and thermodynamic stability, due to the stabilization effect of the Be element by forming twelve classical two-centre–two-electron (2c–2e) σ-bonds and five multicenter 6c–2e π-bonds. There are ten π electrons in a unit cell, which satisfies the Huckel rule [4n + 2] (n = 2), indicating the Be2N6 monolayer aromaticity. As a result, the Be2N6 monolayer has an ultra-high mechanical strength of up to 200 J m−2. Particle-swarm optimization (PSO) computations reveal that a cyclo-N6-containing Be2N6 monolayer is the lowest-energy configuration in 2D forms with a stoichiometry of 1 : 3, and therefore could be synthesized experimentally. Furthermore, the Be2N6 monolayer is an indirect semiconductor with a band gap of 1.71 eV at the hybrid functional level, close to that of the bulk amorphous silicon ∼1.6 eV widely used in solar cells. At this point, the high electron mobility of up to ∼104 cm2 V−1 s−1 and visible-light absorption of ∼105 cm−1 are observed for the Be2N6 monolayer. If realized, it will not only enrich the knowledge of the bonding nature of nitrogen but could also have potential applications in electronics and optoelectronics.
Ashley S. Williams - One of the best experts on this subject based on the ideXlab platform.
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Novel Rubidium Poly-Nitrogen Materials at High Pressure
The Journal of chemical physics, 2017Co-Authors: Ashley S. Williams, Brad A. Steele, Ivan OleynikAbstract:First-principles crystal structure search is performed to predict novel rubidium poly-nitrogen materials at high pressure by varying the stoichiometry, i.e., relative quantities of the constituent rubidium and nitrogen atoms. Three compounds of high nitrogen content, RbN5, RbN2, and Rb4N6, are discovered. Rubidium pentazolate (RbN5) becomes thermodynamically stable at pressures above 30 GPa. The charge transfer from Rb to N atoms enables aromaticity in cyclo-N5− while increasing the ionic bonding in the crystal. Rubidium pentazolate can be synthesized by compressing rubidium azide (RbN3) and nitrogen (N2) precursors above 9.42 GPa, and its experimental discovery is aided by calculating the Raman spectrum and identifying the features attributed to N5− modes. The two other interesting compounds, RbN2 containing infinitely long single-bonded nitrogen chains and Rb4N6 consisting of single-bonded N6 Hexazine rings, become thermodynamically stable at pressures exceeding 60 GPa. In addition to the compounds with...
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Novel Rubidium Poly-Nitrogen Materials at High Pressure
arXiv: Materials Science, 2017Co-Authors: Ashley S. Williams, Brad A. Steele, Van I. OleynikAbstract:First-principles crystal structure search is performed to predict novel rubidium poly-nitrogen materials at high pressure by varying the stoichiometry, i. e. relative quantities of the constituent rubidium and nitrogen atoms. Three compounds of high nitrogen content, RbN_{5}, RbN_{2}, and Rb_{4}N_{6}, are discovered. Rubidium pentazolate (RbN5) becomes thermodynamically stable at pressures above \unit[30]{GPa}. The charge transfer from Rb to N atoms enables aromaticity in cyclo-N_{^{_{5}}}^{-} while increasing the ionic bonding in the crystal. Rubidium pentazolate can be synthesized by compressing rubidium azide (RbN3) and nitrogen (N2) precursors above \unit[9.42]{GPa}, and its experimental discovery is aided by calculating the Raman spectrum and identifying the features attributed to N_{^{_{5}}}^{-} modes. The two other interesting compounds, RbN2 containing infinitely-long single-bonded nitrogen chains, and Rb_{4}N_{6} consisting of single-bonded N_{6} Hexazine rings, become thermodynamically stable at pressures exceeding \unit[60]{GPa}. In addition to the compounds with high nitrogen content, Rb_{3}N_{3}, a new compound with 1:1 RbN stoichiometry containing bent N_{3} azides is found to exist at high pressures.
Li Yafei - One of the best experts on this subject based on the ideXlab platform.
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Benzene-like N 6 Rings in Be 2 N 6 Monolayer: a Stable 2D Semiconductor with High Carrier Mobility
RSC, 2017Co-Authors: Li Feng, Yu Wang, Wu Hong, Liu Zhifa, Aeberhard Urs, Li YafeiAbstract:Designing new two-dimensional (2D) semiconductors with high carrier mobilities is highly desirable for material innovation, especially when the configuration has novel topological properties. Here, we proposed a first-principles-based design of a 2D crystal, namely a Be2N6 monolayer. In which, each N atom is shared by two neighboring N atoms and one Be atom, forming a novel moiety of benzene-like N6 rings. Rather than the instability of Hexazine, the Be2N6 monolayer has a moderate cohesive energy, good kinetic and thermodynamic stability, due to the stabilization effect of the Be element by forming twelve classical two-centre–two-electron (2c–2e) σ-bonds and five multicenter 6c–2e π-bonds. There are ten π electrons in a unit cell, which satisfies the Hückel rule [4n + 2] (n = 2), indicating the Be2N6 monolayer aromaticity. As a result, the Be2N6 monolayer has an ultra-high mechanical strength of up to 200 J m−2. Particle-swarm optimization (PSO) computations reveal that a cyclo-N6-containing Be2N6 monolayer is the lowest-energy configuration in 2D forms with a stoichiometry of 1 : 3, and therefore could be synthesized experimentally. Furthermore, the Be2N6 monolayer is an indirect semiconductor with a band gap of 1.71 eV at the hybrid functional level, close to that of the bulk amorphous silicon ∼1.6 eV widely used in solar cells. At this point, the high electron mobility of up to ∼104 cm2 V−1 s−1 and visible-light absorption of ∼105 cm−1 are observed for the Be2N6 monolayer. If realized, it will not only enrich the knowledge of the bonding nature of nitrogen but could also have potential applications in electronics and optoelectronics