Rapid Synthesis of Sub-5 nm Sized Cubic Boron Nitride Nanocrystals with High-Piezoelectric Behavior via Electrochemical Shock

Abstract

A key challenge in current superhard materials research is the design of novel superhard nanocrystals (NCs) whereby new and unexpected properties may be predicted. Cubic boron nitride (c-BN) is a superhard material which ranks next to diamond; however, downsizing c-BN material below the 10 nm scale is rather challenging, and the interesting new properties of c-BN NCs remain unexplored and wide open. Herein we report an electrochemical shock method to prepare uniform c-BN NCs with a lateral size of only 3.4 ± 0.6 nm and a thickness of only 0.74 ± 0.3 nm at ambient temperature and pressure. The fabrication process is simple and fast, with c-BN NCs produced in just a few minutes. Most interestingly, the NCs exhibit excellent piezoelectric performance with a large recordable piezoelectric coefficient of 25.7 pC/N, which is almost 6 times larger than that from bulk c-BN and even competitive to conventional piezoelectric materials. The phenomenon of enhancement in the piezoelectric properties of BN NCs might arise from the nanoscale surface effect and nanoscale shape effect of BN NCs. This work paves an interesting route for exploring new properties of superhard NCs.

Chemical Decoration of Boron Nitride Nanotubes Using the Billups-Birch Reaction: Toward Enhanced Thermostable Reinforced Polymer and Ceramic Nanocomposites

“…Another noticeable feature from the infrared spectra of f-BNNT is the appearance of peaks at 1090 and 1150 cm −1 . The first is consistent with the values reported for the sp 3 environment in cubic boron nitride, 36,37 which is indicative of a change in hybridization due to the attachment of the alkyl moieties to the boron atom. The latter vibration has been reported to correspond to a B−C bond.…”

Versatile Cutting Method for Producing Fluorescent Ultrasmall MXene Sheets

“…7−9 The quantum confinement effects in these systems with reduced space dimensions would modify electronic and optical properties of these structures, which is important for advancement in both fundamental science and industrial technology fields. 10,11 Although it is recognized that efficient cleavage of inorganic lamellar compounds into individual layers and simultaneously reducing the lateral size of monolayered sheets would offer unexpected opportunities, 12,13 the related studies are rather limited because the bonds within host layers are usually very strong covalent bonds. An intensive reaction may yield breakage of unit layers into smaller parts, but in most cases, damage to the intrinsic chemical structure of the materials would also unavoidably happen to some extent.…”

Materials, Structures, and Functions for Flexible and Stretchable Biomimetic Sensors

“…Self-powered sensors exhibit favorable potentials in fabricating self-driven flexible smart electronics due to the strain-induced voltage and current. We prepared a piezoelectric sensor based on c- BN nanocrystals, revealing a recordable piezoelectric coefficient of 25.7 pC/N . In addition, we investigated vertical piezoelectricity of the CdS nanosheet at atomic scale by in situ scanning Kelvin force microscopy, showing a vertical piezoelectric coefficient up to 33 pm·V –1 , which is much larger than that of the bulk.…”

“…We prepared a piezoelectric sensor based on c-BN nanocrystals, revealing a recordable piezoelectric coefficient of 25.7 pC/N. 8 In addition, we investigated vertical piezoelectricity of the CdS nanosheet at atomic scale by in situ scanning Kelvin force microscopy, showing a vertical piezoelectric coefficient up to 33 pm•V −1 , which is much larger than that of the bulk. It may pave the way to positioning an object with extreme precision.…”

“…The operation principle of the biological response to external stimuli is a smart organization of sensory, nervous, and locomotor systems that correspond to integrated functions, such as the input, transmission, and processing of information, as well as actuation . Inspired by these special properties, novel materials with responsive behavior upon exposure to multiparameter stimulus are developed to fabricate new types of flexible and stretchable biomimetic sensors. − These are generally considered as “smart” electronic components on account of the correspondence to living organisms.…”