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1. Asymmetric twins in boron rich boron carbide

   https://doi.org/10.1039/C8CP01429A  

   Yang, Xiaokun; Goddard, William A.; An, Qi (January 2018, Physical Chemistry Chemical Physics)

   Twin boundaries (TBs) play an essential role in enhancing the mechanical, electronic and transport properties of polycrystalline materials. However, the mechanisms are not well understood. In particular, we considered that they may play an important role in boron rich boron carbide (B vr BC), which exhibits promising properties such as low density, super hardness, high abrasion resistance, and excellent neutron absorption. Here, we apply first-principles-based simulations to identify the atomic structures of TBs in B vr BC and their roles for the inelastic response to applied stresses. In addition to symmetric TBs in B vr BC, we identified a new type of asymmetric twin that constitutes the phase boundaries between boron rich boron carbide (B 13 C 2 ) and B vr BC (B 14 C). The predicted mechanical response of these asymmetric twins indicates a significant reduction of the ideal shear strength compared to single crystals B 13 C 2 and B 14 C, suggesting that the asymmetric twins facilitate the disintegration of icosahedral clusters under applied stress, which in turn leads to amorphous band formation and brittle failure. These results provide a mechanistic basis towards understating the roles of TBs in B vr BC and related superhard ceramics. 

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2. Recent progress on the investigations of boron clusters and boron-based materials (II): The analogy between boron and carbon chemistry

   https://doi.org/10.1360/SSC-2024-0119  

   Ma, Yan-Na; Li, Wan-Lu; Chen, Teng-Teng; Chen, Xuenian; Li, Jun; Wang, Lai-Sheng (September 2024, SCIENTIA SINICA Chimica)
3. Phonon Lifetimes in Boron‐Isotope‐Enriched Graphene‐ Hexagonal Boron Nitride Devices

   https://doi.org/10.1002/pssr.202200030  

   Brasington, Alexandra; Liu, Song; Taniguchi, Takashi; Watanabe, Kenji; Edgar, James H.; LeRoy, Brian J.; Sandhu, Arvinder (March 2022, physica status solidi (RRL) – Rapid Research Letters)

   Using hexagonal boron nitride (hBN) as a substrate for graphene has shown faster carrier cooling which makes it ideal for high‐power graphene‐based devices. However, the effect of using boron‐isotope‐enriched hBN has not been explored. Herein, femtosecond pump‐probe spectroscopy is utilized to measure and compare the time dynamics of photo‐excited carriers in graphene‐hBN heterostructures for hBN with the natural distribution of boron isotopes (20%¹⁰B and 80%¹¹B) and hBN enriched to 100%¹⁰B and¹¹B. The carriers cool down faster for systems with isotopically pure hBN substrates by a factor of ≈1.7 times. This difference in relaxation times arises from the interfacial coupling between carriers in graphene and the hBN phonon modes. The results show that the boron isotopic purity of the hBN substrate can help to reduce the hot phonon bottleneck that limits the cooling in graphene devices. 

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4. Probing the structures and bonding of size-selected boron and doped-boron clusters

   https://doi.org/10.1039/c9cs00233b  

   Jian, Tian; Chen, Xuenian; Li, Si-Dian; Boldyrev, Alexander I.; Li, Jun; Wang, Lai-Sheng (January 2019, Chemical Society Reviews)

   Because of their interesting structures and bonding and potentials as motifs for new nanomaterials, size-selected boron clusters have received tremendous interest in recent years. In particular, boron cluster anions (B n − ) have allowed systematic joint photoelectron spectroscopy and theoretical studies, revealing predominantly two-dimensional structures. The discovery of the planar B 36 cluster with a central hexagonal vacancy provided the first experimental evidence of the viability of 2D borons, giving rise to the concept of borophene. The finding of the B 40 cage cluster unveiled the existence of fullerene-like boron clusters (borospherenes). Metal-doping can significantly extend the structural and bonding repertoire of boron clusters. Main-group metals interact with boron through s/p orbitals, resulting in either half-sandwich-type structures or substitutional structures. Transition metals are more versatile in bonding with boron, forming a variety of structures including half-sandwich structures, metal-centered boron rings, and metal-centered boron drums. Transition metal atoms have also been found to be able to be doped into the plane of 2D boron clusters, suggesting the possibility of metalloborophenes. Early studies of di-metal-doped boron clusters focused on gold, revealing ladder-like boron structures with terminal gold atoms. Recent observations of highly symmetric Ta 2 B 6 − and Ln 2 B n − ( n = 7–9) clusters have established a family of inverse sandwich structures with monocyclic boron rings stabilized by two metal atoms. The study of size-selected boron and doped-boron clusters is a burgeoning field of research. Further investigations will continue to reveal more interesting structures and novel chemical bonding, paving the foundation for new boron-based chemical compounds and nanomaterials. 

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5. Reactivity of Boron Nitride Nanomaterials with Phosphoric Acid and Its Application in the Purification of Boron Nitride Nanotubes

   https://doi.org/10.1021/acs.chemmater.3c01424  

   Shumard, Kevin R; Acapulco, Jesus_A I; Pasquali, Matteo; Martí, Angel A (January 2024, Chemistry of Materials)