Research summary
Large-area hexagonal boron nitride (h-BN) films two to five atomic layers thick were grown by chemical vapor deposition on metal foils and then transferred to arbitrary substrates; the films exhibited an optical energy bandgap of 5.5 eV and high broadband transparency, and nanoindentation measurements yielded a 2D elastic modulus in the 200-500 N/m range, corroborated by first-principles mechanical calculations. The combination of wide bandgap, atomically smooth surface, and low dielectric loss positions monolayer-to-few-layer h-BN as a complementary 2D dielectric substrate for graphene electronics that suppresses substrate-induced carrier scattering relative to amorphous SiO2 [1]. Bulk graphitic carbon nitride (g-C3N4) was exfoliated by a simple liquid-phase process to produce nanosheets of approximately 2 nm thickness with an N/C atomic ratio of 1.31 and an optical bandgap of 2.65 eV; the nanosheets exhibited photocatalytic activity for hydrogen evolution under visible-light illumination, demonstrating a metal-free, scalable route to a visible-light water-splitting catalyst based on a layered organic semiconductor [2]. Graphene quantum dots (GQDs) — edge-bound nanometer-scale graphene fragments with size-tunable optical and electronic properties — were synthesised by acid-treating commercially available pitch-based carbon fibres rather than via lithography or top-down graphene-oxide breakdown; the chemical exfoliation broke down the stacked graphitic submicrometer domains in the fibres, producing GQDs in scalable quantities with size distributions controlled by the reaction temperature and acid stoichiometry, giving an inexpensive feedstock-driven route to photoluminescent GQDs [3]. Intrinsic structural defects in CVD-grown monolayer molybdenum disulfide (MoS2) — point defects, dislocations, grain boundaries, and edges — were characterised at atomic resolution by aberration-corrected TEM imaging and combined with first-principles calculations to map the formation energy, atomic structure, and electronic signatures of each defect type. The study links defect morphology to electronic transport and optoelectronic behaviour in monolayer-MoS2 devices, providing a defect-physics baseline for transition-metal-dichalcogenide device engineering [4].
Recent publications
- High-efficiency two-dimensional Ruddlesden–Popper perovskite solar cellsDOI
- Large-scale synthesis of carbon nanotubesDOI
- Large Scale Growth and Characterization of Atomic Hexagonal Boron Nitride LayersDOI
- New insights into the structure and reduction of graphite oxideDOI
- Exfoliated Graphitic Carbon Nitride Nanosheets as Efficient Catalysts for Hydrogen Evolution Under Visible LightDOI
- Graphene Quantum Dots Derived from Carbon FibersDOI
- Vertical and in-plane heterostructures from WS2/MoS2 monolayersDOI
- Atomic layers of hybridized boron nitride and graphene domainsDOI
- Intrinsic Structural Defects in Monolayer Molybdenum DisulfideDOI
- Vapour phase growth and grain boundary structure of molybdenum disulphide atomic layersDOI
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Email Pulickel M. Ajayan 6-12 months before your application deadline. Read several recent papers and reference specific work in your message. Use our how to email a Japanese professor guide for the proven email structure.
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External profiles
- ORCID: https://orcid.org/0000-0001-8323-7860
- OpenAlex: openalex.org
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