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1.
Anna Chandrasekar Murali Prakash Nayak Shashwat Nayak Sabyasachi Das Dr. Satyaprasad P. Senanayak Prof. Krishnan Venkatasubbaiah 《Angewandte Chemie (International ed. in English)》2023,62(11):e202216871
Development of new n-type semiconductors with tunable band gap and dielectric constant has significant implication in dissociating bound charge carrier relevant for demonstrating high performance optoelectronic devices. Boron-β-thioketonates (MTDKB), analogues to boron-β-diketonates containing a sulfur atom in the framework of β-diketones were synthesized. Bulk transport measurement exhibited an outstanding bulk electron mobility of ≈0.003 cm2 V−1 s−1, which is among the best values reported till date in these class of semiconducting materials and correspondingly a single junction photo responsivity of upto 6 mA W−1 was obtained. This new family of O,S-chelated boron compounds exhibited luminescence in the far red/near-infrared region. The remarkable red shift of 89 nm (fluorescence) observed for 4 a in comparison with analogues boron-β-diketonate signifies the importance of sulfur in these molecules. MTDKBs with amine functionality have also been investigated as an ON/OFF fluorescent sensor. 相似文献
2.
Tian Sun Shuo Li Lei Zhang Yuxi Xu 《Angewandte Chemie (International ed. in English)》2023,62(27):e202301865
Efficient and scalable production of high-quality and processable two-dimensional (2D) polymers are highly desired but have not yet been reported. Herein, we demonstrate a convenient noncovalent functionalization strategy for producing highly uniform, aqueous processable and semiconducting 2D triazine polymers. Experimental and theoretical analysis reveal that the aromatic amphiphilic 1-pyrenebutyrate can adsorb and intercalate into the interlayer of bulk crystalline covalent triazine framework (CTF) through noncovalent π-π stacking interaction between the pyrene moiety and the porous basal plane of 2D triazine polymer layer, which greatly facilitate the exfoliation of CTF in water in large scale. The as-prepared highly water-dispersible single-layer/few-layer 2D triazine polymer nanosheets can be easily processed into ultralight aerogels with a density of 5–15 mg cm−3, which can be further shaped into mechanically strong films upon simple compression. This noncovalent functionalization not only improve the dispersibility and processability of 2D triazine polymer, but also optimize its band structure and promote the photogenerated carrier separation via an interesting surface molecule doping effect, thus resulting in a remarkable photocatalytic hydrogen evolution rate of 1249 μmol h−1 (24980 μmol g−1 h−1) and apparent quantum efficiency up to 27.2 % at 420 nm for the 2D triazine polymer, outperforming most metal-free photocatalysts ever reported. 相似文献
3.
Tianyu Wu Dr. Xingjiang Wu Lianhui Li Mingming Hao Prof. Guan Wu Prof. Ting Zhang Prof. Su Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(52):24008-24017
A 2D boron nanosheet that exhibits high theoretical capacitance, around four times that of graphene, is a significant supercapacitor electrode. However, its bulk structure with low interlaminar conduction and porosity restricts the charge transfer, ion diffusion, and energy density. Herein, we develop a new 2D hetero-nanosheet made of anisotropic boron–carbon nanosheets (ABCNs) by B−C chemical bonds via gas-phase exfoliation and condensation bottom-up strategy. The ABCNs are constructed into high flexible supercapacitor electrode by microfluidic electrospinning. The ABCN electrode greatly promotes smooth migration and excessive storage of electrolyte ions due to large interlayer conductivity, ionic pathways, and accessible surfaces. The flexible supercapacitor delivers ultrahigh volumetric energy density of 167.05 mWh cm−3 and capacitance of 534.5 F cm−3. A wearable energy-sensor system is designed to stably monitor physiological signals. 相似文献
4.
Chuang Hou Guoan Tai Jinqian Hao Lihang Sheng Bo Liu Zitong Wu 《Angewandte Chemie (International ed. in English)》2020,59(27):10819-10825
Borophene sheets have been synthesized in recent experiments, but the metallic nature and structural instability of the sheets seriously prevent emerging applications. Hydrogenated borophene has been predicted as an ideal material for nanoelectronic applications due to its high stability as well as excellent electronic and mechanical properties. However, the fabrication of hydrogenated borophene is still a great challenge. Here, we demonstrate that hydrogenated borophenes in large quantities can be prepared without any metal substrates by a stepwise in‐situ thermal decomposition of sodium borohydride under hydrogen as the carrier gas. The borophenes with good crystallinity exhibit superior stability in strong acid or base solvents. The structure of the grown borophene is in good agreement with the predicted semiconducting α‐boron sheet. A fabricated borophene‐based memory device shows a high ON/OFF‐current ratio of 3×103 and a low operating voltage of less than 0.35 V as well as good stability. 相似文献
5.
Prof. Dr. Zhuhua Zhang Dr. Sharmila N. Shirodkar Dr. Yang Yang Prof. Dr. Boris I. Yakobson 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(48):15623-15628
Boron nanostructures are easily charged but how charge carriers affect their structural stability is unknown. We combined cluster expansion methods with first‐principles calculations to analyze the dependence of the preferred structure of two‐dimensional (2D) boron, or “borophene”, on charge doping controlled by a gate voltage. At a reasonable doping level of 3.12×1014 cm−2, the hollow hexagon concentration in the ground state of 2D boron increases to 1/7 from 1/8 in its charge‐neutral state. The numerical result for the dependence of hollow hexagon concentration on the doping level is well described by an analytical method based on an electron‐counting rule. Aside from in‐plane electronic bonding, the hybridization among out‐of‐plane boron orbitals is crucial for determining the relative stability of different sheets at a given doping level. Our results offer new insight into the stability mechanism of 2D boron and open new ways for the control of the lattice structure during formation. 相似文献
6.
Hafeesudeen Sahabudeen Dr. Haoyuan Qi Marco Ballabio Dr. Miroslav Položij Dr. Selina Olthof Rishi Shivhare Dr. Yu Jing SangWook Park Kejun Liu Dr. Tao Zhang Ji Ma Dr. Bernd Rellinghaus Prof. Dr. Stefan Mannsfeld Prof. Dr. Thomas Heine Prof. Dr. Mischa Bonn Prof. Dr. Enrique Cánovas Prof. Dr. Zhikun Zheng Prof. Dr. Ute Kaiser Dr. Renhao Dong Prof. Dr. Xinliang Feng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(15):6084-6092
Single-layer and multi-layer 2D polyimine films have been achieved through interfacial synthesis methods. However, it remains a great challenge to achieve the maximum degree of crystallinity in the 2D polyimines, which largely limits the long-range transport properties. Here we employ a surfactant-monolayer-assisted interfacial synthesis (SMAIS) method for the successful preparation of porphyrin and triazine containing polyimine-based 2D polymer (PI-2DP) films with square and hexagonal lattices, respectively. The synthetic PI-2DP films are featured with polycrystalline multilayers with tunable thickness from 6 to 200 nm and large crystalline domains (100–150 nm in size). Intrigued by high crystallinity and the presence of electroactive porphyrin moieties, the optoelectronic properties of PI-2DP are investigated by time-resolved terahertz spectroscopy. Typically, the porphyrin-based PI-2DP 1 film exhibits a p-type semiconductor behavior with a band gap of 1.38 eV and hole mobility as high as 0.01 cm2 V−1 s−1, superior to the previously reported polyimine based materials. 相似文献
7.
Arno Knappschneider Dr. Christian Litterscheid Nathan C. George Dr. Jakoah Brgoch Norbert Wagner Prof. Dr. Johannes Beck Dr. Joshua A. Kurzman Prof. Dr. Ram Seshadri Prof. Dr. Barbara Albert 《Angewandte Chemie (International ed. in English)》2014,53(6):1684-1688
Tetraborides of chromium and manganese exhibit an unusual boron‐atom framework that resembles the hypothetical tetragonal diamond. They are believed to be very hard. Single crystals of MnB4 have now been grown. The compound crystallizes in the monoclinic crystal system (space group P21/c) with a structure that has four crystallographically independent boron‐atom positions, as confirmed by 11B MAS‐NMR spectroscopy. An unexpected short distance between the Mn atoms suggests a double Mn–Mn bond and is caused by Peierls distortion. The structure was solved using group‐subgroup‐relationships. DFT calculations indicate MnI centers and paramagnetism, as confirmed by magnetic measurements. The density of states shows a pseudo‐band gap at the Fermi energy and semiconducting behavior was observed for MnB4. 相似文献
8.
《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1991,47(3-4):477-483
The absolute infrared intensities of the ν2, ν3 and ν6 bands of formic acid have been evaluated in a 480 L White cell system using FTIR and ion chromatography techniques. The values obtained are, respectively; (4.2 ± 0.2) × 10−17 cm molec−1 for the ν6 band, (4.8 ± 0.2) × 10−17 cm molec−1 for the ν3 band and (0.57 ± 0.04) × 10−17 cm molec−1 for the ν2 band. The air broadening coefficient of transitions in the ν6 band, has been measured using a tunable diode laser spectrometer, equal to (0.101 ± 0.005) cm−1 atm−1 (half width at half maximum). A computer search has been performed to find absorption lines of formic acid suitable for second derivative tunable diode laser measurement of this gas in ambient air. 相似文献
9.
Dr. Xin Wang Dr. Junjie He Dr. Benqing Zhou Dr. Youming Zhang Dr. Jiatao Wu Dr. Rui Hu Prof. Liwei Liu Prof. Jun Song Prof. Junle Qu 《Angewandte Chemie (International ed. in English)》2018,57(28):8668-8673
As a highly stable band gap semiconductor, antimonene is an intriguing two‐dimensional (2D) material in optoelectronics. However, its short layer distance and strong binding energy make it challenging to prepare high‐quality large 2D antimonene; therefore, its predicted tunable band gap has not been experimentally confirmed. Now, an approach to prepare smooth and large 2D antimonene with uniform layers that uses a pregrinding and subsequent sonication‐assisted liquid‐phase exfoliation process has been established. Mortar pregrinding provides a shear force along the layer surfaces, forming large, thin antimony plates, which can then easily be exfoliated into smooth, large antimonene, avoiding long sonication times and antimonene destruction. The resulting antimonene also enabled verification of the tunable band gap from 0.8 eV to 1.44 eV. Hole extraction and current enhancement by about 30 % occurred when the antimonene was used as a hole transport layer in perovskite solar cells. 相似文献
10.
Wan‐Lu Li Tian Jian Xin Chen Teng‐Teng Chen Dr. Gary V. Lopez Prof. Dr. Jun Li Prof. Dr. Lai‐Sheng Wang 《Angewandte Chemie (International ed. in English)》2016,55(26):7358-7363
Monolayer‐boron (borophene) has been predicted with various atomic arrangements consisting of a triangular boron lattice with hexagonal vacancies. Its viability was confirmed by the observation of a planar hexagonal B36 cluster with a central six‐membered ring. Here we report a planar boron cluster doped with a transition‐metal atom in the boron network (CoB18?), suggesting the prospect of forming stable hetero‐borophenes. The CoB18? cluster was characterized by photoelectron spectroscopy and quantum chemistry calculations, showing that its most stable structure is planar with the Co atom as an integral part of a triangular boron lattice. Chemical bonding analyses show that the planar CoB18? is aromatic with ten π‐electrons and the Co atom has strong covalent interactions with the surrounding boron atoms. The current result suggests that transition metals can be doped into the planes of borophenes to create metallo‐borophenes, opening vast opportunities to design hetero‐borophenes with tunable chemical, magnetic, and optical properties. 相似文献
11.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(32):9679-9683
Despite its electron deficiency, boron is versatile in forming multiple bonds. Transition‐metal–boron double bonding is known, but boron–metal triple bonds have been elusive. Two bismuth boron cluster anions, BiB2O− and Bi2B−, containing triple and double B−Bi bonds are presented. The BiB2O− and Bi2B− clusters are produced by laser vaporization of a mixed B/Bi target and characterized by photoelectron spectroscopy and ab initio calculations. Well‐resolved photoelectron spectra are obtained and interpreted with the help of ab initio calculations, which show that both species are linear. Chemical bonding analyses reveal that Bi forms triple and double bonds with boron in BiB2O− ([Bi≡B−B≡O]−) and Bi2B− ([Bi=B=Bi]−), respectively. The Bi−B double and triple bond strengths are calculated to be 3.21 and 4.70 eV, respectively. This is the first experimental observation of Bi−B double and triple bonds, opening the door to design main‐group metal–boron complexes with multiple bonding. 相似文献
12.
Shaofeng Huang Dr. Ji Yong Choi Qiucheng Xu Dr. Yinghua Jin Prof. Jihye Park Prof. Wei Zhang 《Angewandte Chemie (International ed. in English)》2023,62(22):e202303538
Two covalent organic frameworks consisting of carbazolylene-ethynylene shape-persistent macrocycles with azine (MC-COF-1) or imine (MC-COF-2) linkages were synthesized via imine condensation. The obtained 2D frameworks are fully conjugated which imparts semiconducting properties. In addition, the frameworks showed high porosity with aligned accessible porous channels along the z axis, serving as an ideal platform for post-synthetic incorporation of I2 into the channels to enable electrical conductivity. The resulting MC-COF-1 showed an electrical conductivity up to 7.8×10−4 S cm−1 at room temperature upon I2 doping with the activation energy as low as 0.09 eV. Furthermore, we demonstrated that the electrical properties of both MC-COFs are switchable between electron-conducting and insulating states by simply implementing doping-regenerating cycles. The knowledge gained in this study opens new possibilities for the future development of tunable conductive 2D organic materials. 相似文献
13.
《Angewandte Chemie (International ed. in English)》2017,56(34):10214-10218
In all known Group 5 transition‐metal dichalcogenide monolayers (MLs), the metal centers carry a spin, and their ground‐state phases are either metallic or semiconducting with indirect band gaps. Here, on grounds of first‐principles calculations, we report that the Haeckelite polytypes 1 S ‐NbX2 (X=S, Se, Te) are diamagnetic direct‐band‐gap semiconductors even though the Nb atoms are in the 4+ oxidation state. In contrast, 1 S ‐VX2 MLs are antiferromagnetically coupled indirect‐band‐gap semiconductors. The 1 S phases are thermodynamically and dynamically stable but of slightly higher energy than their 1 H and 1 T ML counterparts. 1 S ‐NbX2 MLs are excellent candidates for optoelectronic applications owing to their small band gaps (between 0.5 and 1 eV). Moreover, 1 S ‐NbS2 shows a particularly high hole mobility of 2.68×103 cm2 V−1 s−1, which is significantly higher than that of MoS2 and comparable to that of WSe2. 相似文献
14.
Teng-Teng Chen Ling Fung Cheung Wei-Jia Chen Joseph Cavanagh Prof. Dr. Lai-Sheng Wang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(35):15372-15377
Multiple bonds between boron and transition metals are known in many borylene (:BR) complexes via metal dπ→BR back-donation, despite the electron deficiency of boron. An electron-precise metal–boron triple bond was first observed in BiB2O− [Bi≡B−B≡O]− in which both boron atoms can be viewed as sp-hybridized and the [B−BO]− fragment is isoelectronic to a carbyne (CR). To search for the first electron-precise transition-metal-boron triple-bond species, we have produced IrB2O− and ReB2O− and investigated them by photoelectron spectroscopy and quantum-chemical calculations. The results allow to elucidate the structures and bonding in the two clusters. We find IrB2O− has a closed-shell bent structure (Cs, 1A′) with BO− coordinated to an Ir≡B unit, (−OB)Ir≡B, whereas ReB2O− is linear (C∞v, 3Σ−) with an electron-precise Re≡B triple bond, [Re≡B−B≡O]−. The results suggest the intriguing possibility of synthesizing compounds with electron-precise M≡B triple bonds analogous to classical carbyne systems. 相似文献
15.
Sheng Yang Antonio Gaetano Ricciardulli Dr. Shaohua Liu Dr. Renhao Dong Dr. Martin R. Lohe Alfons Becker Marco A. Squillaci Prof. Paolo Samorì Prof. Klaus Müllen Prof. Xinliang Feng 《Angewandte Chemie (International ed. in English)》2017,56(23):6669-6675
To bridge the gap between laboratory-scale studies and commercial applications, mass production of high quality graphene is essential. A scalable exfoliation strategy towards the production of graphene sheets is presented that has excellent yield (ca. 75 %, 1–3 layers), low defect density (a C/O ratio of 21.2), great solution-processability, and outstanding electronic properties (a hole mobility of 430 cm2 V−1 s−1). By applying alternating currents, dual exfoliation at both graphite electrodes enables a high production rate exceeding 20 g h−1 in laboratory tests. As a cathode material for lithium storage, graphene-wrapped LiFePO4 particles deliver a high capacity of 167 mAh g−1 at 1 C rate after 500 cycles. 相似文献
16.
Dr. Feng-Yin Li Jia-Qi Zhang Prof. Dr. Hong-Xing Zhang Prof. Dr. Jian Wang Prof. Dr. Ran Jia 《Chemphyschem》2023,24(10):e202200813
In this work, two kinds of BN-nanowires (BNnws): a-BNnw and d-BNnw, respectively composed of azo (N−N) and diboron (B−B) bonds, are proposed with the aid of the first-principles simulations. Their structural stabilities are carefully verified from the energetics, lattice dynamics, and thermodynamic perspectives. Similar to the other common boron nitride polymorph, the a-BNnw and d-BNnw are semiconductors with relatively wide band gaps of 3.256 and 4.631 eV at the HSE06 level, respectively. The corresponding projected DOS patterns point out that their band edges are composed of different atomic species, which can help with the separation of their excitons. The band gaps can be manipulated monotonically by axial strains within the elastic ranges. The major charge carriers are electron holes. Significantly, a-BNnw possesses very high carrier mobilities around 0.44×104 cm2 V−1 s−1. 相似文献
17.
Prof. Guoan Tai Tingsong Hu Dr. Yungang Zhou Xufeng Wang Dr. Jizhou Kong Tian Zeng Yuncheng You Qin Wang 《Angewandte Chemie (International ed. in English)》2015,54(51):15473-15477
Two‐dimensional boron materials have recently attracted extensive theoretical interest because of their exceptional structural complexity and remarkable physical and chemical properties. However, such 2D boron monolayers have still not been synthesized. In this report, the synthesis of atomically thin 2D γ‐boron films on copper foils is achieved by chemical vapor deposition using a mixture of pure boron and boron oxide powders as the boron source and hydrogen gas as the carrier gas. Strikingly, the optical band gap of the boron film was measured to be around 2.25 eV, which is close to the value (2.07 eV) determined by first‐principles calculations, suggesting that the γ‐B28 monolayer is a fascinating direct band gap semiconductor. Furthermore, a strong photoluminescence emission band was observed at approximately 626 nm, which is again due to the direct band gap. This study could pave the way for applications of two‐dimensional boron materials in electronic and photonic devices. 相似文献
18.
Dr. Keke Guo Weijun Li Yuhong He Xiaopeng Feng Jinmei Song Wanting Pan Wei Qu Prof. Bai Yang Prof. Haotong Wei 《Angewandte Chemie (International ed. in English)》2023,62(23):e202303445
The low-dimensional halide perovskites have attracted increasing attention due to their improved moisture stability, reduced defects, and suppressed ions migration in many optoelectronic devices such as solar cells, light-emitting diodes, X-ray detectors, and so on. However, they are still limited by their large band gap and short charge carriers’ diffusion length. Here, we demonstrate that the introduction of metal ions into organic interlayers of two-dimensional (2D) perovskite by cross-linking the copper paddle-wheel cluster-based lead bromide ([Cu(O2C−(CH2)3−NH3)2]PbBr4) perovskite single crystals with coordination bonds can not only significantly reduce the perovskite band gap to 0.96 eV to boost the X-ray induced charge carriers, but can also selectively improve the charge carriers’ transport along the out-of-plane direction and blocking the ions motion paths. The [Cu(O2C−(CH2)3−NH3)2]PbBr4 single-crystal device can reach a record charges/ions collection ratio of 1.69×1018±4.7 % μGyair−1 s, and exhibit a large sensitivity of 1.14×105±7% μC Gyair−1 cm−2 with the lowest detectable dose rate of 56 nGyair s−1 under 120 keV X-rays irradiation. In addition, [Cu(O2C−(CH2)3−NH3)2]PbBr4 single-crystal detector exposed to the air without any encapsulation shows excellent X-ray imaging capability with long-term operational stability without any attenuation of 120 days. 相似文献
19.
20.
Exploring a Lead‐free Semiconducting Hybrid Ferroelectric with a Zero‐Dimensional Perovskite‐like Structure
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Dr. Zhihua Sun Aurang Zeb Sijie Liu Chengmin Ji Tariq Khan Dr. Lina Li Prof. Maochun Hong Prof. Junhua Luo 《Angewandte Chemie (International ed. in English)》2016,55(39):11854-11858
Perovskite lead halides (CH3NH3PbI3) have recently taken a promising position in photovoltaics and optoelectronics because of remarkable semiconducting properties and possible ferroelectricity. However, the potential toxicity of lead arouses great environmental concern for widespread application. A new chemically tailored lead‐free semiconducting hybrid ferroelectric is reported, N‐methylpyrrolidinium)3Sb2Br9 ( 1 ), which consists of a zero‐dimensional (0‐D) perovskite‐like anionic framework connected by corner‐ sharing SbBr6 coordinated octahedra. It presents a large ferroelectric spontaneous polarization of approximately 7.6 μC cm?2, as well as notable semiconducting properties, including positive temperature‐dependent conductivity and ultraviolet‐sensitive photoconductivity. Theoretical analysis of electronic structure and energy gap discloses a dominant contribution of the 0‐D perovskite‐like structure to the semiconducting properties of the material. This finding throws light on the rational design of new perovskite‐like hybrids, especially lead‐free semiconducting ferroelectrics. 相似文献