Nitrogenated holey two-dimensional structures

Mahmood, Javeed; Lee, Eun Kwang; Jung, Minbok; Shin, Dongbin; Jeon, In Yup; Jung, Sun Min; Choi, Hyun Jung; Seo, Jeong Min; Bae, Seo Yoon; Sohn, So Dam; Park, Noejung; Oh, Joon Hak; Shin, Hong Ju; Baek, Jong‐Beom

doi:10.1038/ncomms7486

Cited by 993 publications

(717 citation statements)

References 33 publications

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“…The 2D PANI crystalline films were fabricated by drop casting of the HAB crystals dissolved in trifluoromethanesulfonic acid on the preheated (140°C) SiO 2 (300 nm)/Si substrate and subsequently heat-treated at 700°C in argon atmosphere for 2 h. The thin flakes were transferred to fresh SiO 2 (300 nm)/Si substrate by PDMS stamping (32). Chromium (Cr, 4 nm) and gold (Au, 40 nm) were thermally evaporated.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Two-dimensional polyaniline (C ₃ N) from carbonized organic single crystals in solid state

Mahmood

Lee

Jung

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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409

205

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The formation of 2D polyaniline (PANI) has attracted considerable interest due to its expected electronic and optoelectronic properties. Although PANI was discovered over 150 y ago, obtaining an atomically well-defined 2D PANI framework has been a longstanding challenge. Here, we describe the synthesis of 2D PANI via the direct pyrolysis of hexaaminobenzene trihydrochloride single crystals in solid state. The 2D PANI consists of three phenyl rings sharing six nitrogen atoms, and its structural unit has the empirical formula of C 3 N. The topological and electronic structures of the 2D PANI were revealed by scanning tunneling microscopy and scanning tunneling spectroscopy combined with a first-principle density functional theory calculation. The electronic properties of pristine 2D PANI films (undoped) showed ambipolar behaviors with a Dirac point of -37 V and an average conductivity of 0.72 S/cm. After doping with hydrochloric acid, the conductivity jumped to 1.41 × 10 3 S/cm, which is the highest value for doped PANI reported to date. Although the structure of 2D PANI is analogous to graphene, it contains uniformly distributed nitrogen atoms for multifunctionality; hence, we anticipate that 2D PANI has strong potential, from wet chemistry to device applications, beyond linear PANI and other 2D materials.was discovered in 1834 (1), the word PANI was first coined in 1947 (2), and PANI garnered immense attention from the scientific community due to its intrinsically conducting nature (3). During the last three decades, PANI has been one of the most extensively studied conducting polymers because of its simple synthesis, low cost, high conductivity, environmental stability, and doping chemistry (4, 5). Linear PANI has found broad applicability in rechargeable batteries (6), electromagnetic shielding (7), nonlinear optics (8), light-emitting devices (9), sensors (10), field effect transistors (11), erasable optical information storage (12), membranes (13), digital memory devices (14) (27)], cyclic, spiral, and complex nanostructures have also been reported (28). However, due to the mechanistic complexity of aniline polymerization, the atomic-scale control of PANI structure has not yet been realized (28). Together with the recent discovery of all-carbon-based 2D graphene and its promising potentials (29), 2D network polymers are galvanizing a new wave of research in the scientific community (30). Here, we, for the first time to our knowledge, report the synthesis of real 2D PANI framework from direct pyrolysis of organic single crystals, hexaaminobenzene trihydrochloride (HAB), at 500°C. This synthetic methodology could serve as a straightforward way for the design and synthesis of other new 2D layered materials with many potential applications, from wet chemistry to devices. Results and DiscussionThe key building block, HAB, as a monomer with six functional groups (M6), was synthesized in a pure crystalline form (Fig. 1A and SI Appendix, Fig. S1) (31). It was observed that the HAB single crystals pyrolyze before mel...

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Section: Methodsmentioning

confidence: 99%

“…To elucidate the electrical properties, field-effect transistors (FETs) were fabricated using 2D PANI flakes as the active layer. The 2D PANI flakes were isolated onto Si wafer with 300-nm-thick SiO 2 by using polydimethylsiloxane (PDMS) stamping from the prepared films (32). Fig.…”

Section: Significancementioning

confidence: 99%

Two-dimensional polyaniline (C ₃ N) from carbonized organic single crystals in solid state

Mahmood

Lee

Jung

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

409

205

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“…Experimentally, monolayer h2D-C 2 N has been successfully isolated and transferred onto insulating substrate. 20 It shows a direct bandgap ∼1.96 eV measured by optical spectroscopy, and a field-effect-transistor fabricated based on it exhibits a high on/off ratio of 10 7 . 20 Without charge doping, h2D-C 2 N is non-magnetic.…”

Section: Introductionmentioning

confidence: 99%

“…20 It shows a direct bandgap ∼1.96 eV measured by optical spectroscopy, and a field-effect-transistor fabricated based on it exhibits a high on/off ratio of 10 7 . 20 Without charge doping, h2D-C 2 N is non-magnetic. Here, using first-principles calculations, we show that ferromagnetic ordering can be easily induced in h2D-C 2 N monolayer by electron doping, and remarkably, in a wide doping range (4 × 10 13 /cm 2 to 8 × 10 13 /cm 2 ) the material is in fact a halfmetal with fully spin-polarized carriers for conduction.…”

Section: Introductionmentioning

confidence: 99%

Tunable half-metallic magnetism in an atom-thin holey two-dimensional C₂N monolayer

et al. 2017

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Exploring two-dimensional (2D) materials with magnetic ordering is a focus of current research. It remains a challenge to achieve tunable magnetism in a material of one-atom-thickness without introducing extrinsic magnetic atoms or defects. Here, based on first-principles calculations, we propose that tunable ferromagnetism can be realized in the recently synthesized holey 2D C 2 N (h2D-C 2 N) monolayer via purely electron doping that can be readily achieved by gating. We show that owing to the prominent van Hove singularity in the band structure, the material exhibits spontaneous ferromagnetism at a relatively low doping density. Remarkably, over a wide doping range of 4×10 13 /cm 2 to 8×10 13 /cm 2 , the system becomes half-metallic, with carriers fully spin-polarized. The estimated Curie temperature can be up to 320 K. Besides gating, we find that the magnetism can also be effectively tuned by lattice strain. Our result identifies h2D-C 2 N as the first material with single-atom-thickness that can host gate-tunable room-temperature half-metallic magnetism, suggesting it as a promising platform to explore nanoscale magnetism and flexible spintronic devices.

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“…The atomically thin g-C2N was developed through wet-chemical reactions [83], which expanded the 2D atomic crystal library. Strictly speaking, g-C2N cannot be classified as an ILC due to the carbon present in the composite.…”

Section: Other Synthetic Systems: M-zno and G-c 2 Nmentioning

confidence: 99%

Introducing Magnetism into 2D Nonmagnetic Inorganic Layered Crystals: A Brief Review from First-Principles Aspects

et al. 2018

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Pioneering explorations of the two-dimensional (2D) inorganic layered crystals (ILCs) in electronics have boosted low-dimensional materials research beyond the prototypical but semi-metallic graphene. Thanks to species variety and compositional richness, ILCs are further activated as hosting matrices to reach intrinsic magnetism due to their semiconductive natures. Herein, we briefly review the latest progresses of manipulation strategies that introduce magnetism into the nonmagnetic 2D and quasi-2D ILCs from the first-principles computational perspectives. The matrices are concerned within naturally occurring species such as MoS 2 , MoSe 2 , WS 2 , BN, and synthetic monolayers such as ZnO and g-C 2 N. Greater attention is spent on nondestructive routes through magnetic dopant adsorption; defect engineering; and a combination of doping-absorbing methods. Along with structural stability and electric uniqueness from hosts, tailored magnetic properties are successfully introduced to low-dimensional ILCs. Different from the three-dimensional (3D) bulk or zero-dimensional (0D) cluster cases, origins of magnetism in the 2D space move past most conventional physical models. Besides magnetic interactions, geometric symmetry contributes a non-negligible impact on the magnetic properties of ILCs, and surprisingly leads to broken symmetry for magnetism. At the end of the review, we also propose possible combination routes to create 2D ILC magnetic semiconductors, tentative theoretical models based on topology for mechanical interpretations, and next-step first-principles research within the domain.

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Nitrogenated holey two-dimensional structures

Cited by 993 publications

References 33 publications

Two-dimensional polyaniline (C ₃ N) from carbonized organic single crystals in solid state

Two-dimensional polyaniline (C ₃ N) from carbonized organic single crystals in solid state

Tunable half-metallic magnetism in an atom-thin holey two-dimensional C₂N monolayer

Introducing Magnetism into 2D Nonmagnetic Inorganic Layered Crystals: A Brief Review from First-Principles Aspects

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Nitrogenated holey two-dimensional structures

Cited by 993 publications

References 33 publications

Two-dimensional polyaniline (C 3 N) from carbonized organic single crystals in solid state

Two-dimensional polyaniline (C 3 N) from carbonized organic single crystals in solid state

Tunable half-metallic magnetism in an atom-thin holey two-dimensional C2N monolayer

Introducing Magnetism into 2D Nonmagnetic Inorganic Layered Crystals: A Brief Review from First-Principles Aspects

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Two-dimensional polyaniline (C ₃ N) from carbonized organic single crystals in solid state

Two-dimensional polyaniline (C ₃ N) from carbonized organic single crystals in solid state

Tunable half-metallic magnetism in an atom-thin holey two-dimensional C₂N monolayer