Crystalline Semiconductor Boron Quantum Dots

Abstract

Zero-dimensional boron structures have always been the focus of theoretical research owing to their abundant phase structures and special properties. Boron clusters have been reported extensively by combining structure searching theories and photoelectron spectroscopy (PES) experiments; however, crystalline boron quantum dots (BQDs) have rarely been reported. Here, we report the preparation of large-scale and uniform crystalline semiconductor BQDs from the expanded bulk boron powders via a facile and efficient probe ultrasonic approach in the acetonitrile solution. The obtained BQDs have 2.46 nm average lateral size and 2.81 nm thickness. Optical measurements demonstrate that a strong quantum confinement effect occurs in the BQDs, implying the increase of the band gap from 1.80 eV for the corresponding bulk to 2.46 eV for the BQDs. By injecting the BQDs into poly­(vinylpyrrolidone) as an active layer, a BQD-based memory device is fabricated that shows a rewriteable nonvolatile memory effect with a low transition voltage of down to 0.5 V and a high on/off switching ratio of 103 as well as a good stability.

Crystalline borophene quantum dots and their derivative boron nanospheres

“…The ultrasmall boron nanoparticles are likely to be prepared by exfoliating the bulk boron through physical and chemical technologies. As expected, boron quantum dots proposed by Tai et al, 14 a new cousin of carbon quantum dots, were synthesized successfully, provoking the growing passion in zero-dimensional crystalline boron nanomaterials. As extraordinary zero-dimensional materials, carbon quantum dots (CQDs) have demonstrated good chemical, electrical, and photoluminescence (PL) characteristics, and offer great potential in drug delivery, sensing, bioimaging, and diagnosis applications.…”

Borophene: Current Status, Challenges and Opportunities

“…Following by the borophene progress, boron clusters are considered as an unit for forming 2D borophene, our group also first reported that large‐scale and crystalline boron quantum dots (BQDs) with semiconducting nature were synthesized successfully by a facile and efficient probe ultrasonic approach using the flocculent boron powders in acetonitrile solution . To obtain the crystalline BQDs, the commercial flocculent boron powder of 30 mg and acetonitrile of 15 mL was respectively added into a three‐necked bottle before the probe ultrasonication process.…”

“…Since the end of the last century, boron nanostructures had been studied, which include zero‐dimensional (0D) clusters and one dimensional (1D) nanotubes. 2D boron sheets, as the most basic units for constructing the boron nanostructures, had attracted great attention in the past two decades . Especially, Boustani, Ismail‐Beigi and Yakobson et al.…”

“…After that, borophene sheets with different phases have been experimentally grown on the extensive substrates of Cu (111), Au (111) and Al (111) . Recently, quasicubic boron sheet with a direct bandgap, crystalline semiconducting boron quantum dots (BQDs), and hydrogenated borophenes (α′‐4H‐borophene) have been successfully prepared in our group, which promote substantial potential applications of the boron nanostructures in next‐generation nanoelectronics.…”

Recent progress in quantum dots based nanocomposite electrodes for rechargeable monovalent metal-ion and lithium metal batteries

“…33,34 In this respect, the last few years have witnessed a tremendous interest in designing quantum dot based nanocomposite hybrids as electrode materials in energy storage devices. Quantum dots (QDs) with particle size <10 nm generally possess amorphous 35–38 to nanocrystalline 39–42 cores with high surface to volume ratios which hold several merits over their micron size particles in terms of enhanced active surface per unit mass for reactions (redox sites) and ion absorption, improved redox kinetics, homogeneous volume expansion/contraction during ion (de)intercalation to buffer lattice distortion, etc. In addition, QDs offer improved solid-state ion diffusion due to the shortening diffusion path, better conductivity along with the enhanced interfacial connection.…”