Insights into the Solution Processing of Non‐van der Waals Boron Carbide

Exfoliation of non-layered materials is crucial to unleash their enormous potential in wide range of applications. However, the presence of strong non-van der Waals interactions in all three dimensions makes exfoliation challenging. Boron carbide (B₄C), known for its high hardness, holds great potential for diverse applications. In this work, B₄C is exfoliated in 29 solvents to determine its Hansen solubility parameters (HSP) and understand the dispersion stability. The experimentally determined HSP values are 19.6, 15.3 and 15.1 MPa^1/2 for dispersive interactions (δ_D), polar interactions (δ_P) and hydrogen bonding interactions (δ_H), respectively. Subsequently, in situ dispersion stability is analyzed qualitatively and quantitatively from the space-time resolved extinction profiles employing an analytical centrifuge. The sedimentation kinetics of B₄C dispersions are analyzed using instability index, integral extinction and sedimentation velocity. B₄C dispersions in solvents like ϵ-caprolactone, isopropyl alcohol, propylene carbonate and formamide exhibited excellent stability. Additionally, B₄C nanosheets are utilized to investigate their field emission properties. These nanosheets exhibit a turn-on electric field of 3.35 V/μm at an emission current density of 1 μA cm^-2, and it delivered a large emission current density of ~375 μA cm^-2 at an applied electric field of 5.7 V/μm.