Efficient and Fast Synthesis of Few‐Layer Black Phosphorus via Microwave‐Assisted Liquid‐Phase Exfoliation

Abstract

High‐quality, few‐layer black‐phosphorus (BP) flakes are prepared in a common organic solvent with very short processing times using microwave‐assisted liquid‐phase exfoliation. A comprehensive range of analysis, combined with density‐functional theory calculations, confirms that the product prepared using the microwave technique is few‐layer BP with small‐ and large‐area flakes. The suspended exfoliated BP sheets show excellent stability, while samples dispersed onto silicon from the suspensions exhibit low oxidation levels after several days in ambient conditions. This straightforward synthesis method is facile, efficient, and extremely fast, and does not involve use of any surfactant or ultrasonication steps and will facilitate future development of phosphorene research.

Efficient Production of Phosphorene Nanosheets via Shear Stress Mediated Exfoliation for Low‐Temperature Perovskite Solar Cells

“…Three main characteristic peaks at around 220, 300, and 370 nm were observed (Figure b). These three strong and sharp peaks are very consistent with previously reported theoretical results and the spectrum of mechanically exfoliated phosphorene . Recently, we reported the preparation of high‐quality few‐layer black phosphorus in N ‐Methyl‐2‐pyrrolidone (NMP) using a novel microwave‐assisted LPE method .…”

“…These three strong and sharp peaks are very consistent with previously reported theoretical results and the spectrum of mechanically exfoliated phosphorene . Recently, we reported the preparation of high‐quality few‐layer black phosphorus in N ‐Methyl‐2‐pyrrolidone (NMP) using a novel microwave‐assisted LPE method . In these studies, we have shown for the first time the benchmark UV–vis spectra for the solution processed phosphorene, highlighting the three major peaks, which are in excellent agreement with the peaks observed for the VFD‐exfoliated phosphorene solution.…”

“…However, in order to efficiently exfoliate the bulk BP crystals, long processing times (several hours) are required, which increases the overall production cost and creates anomalous structural defects in the as‐produced nanosheets. These issues have led to significant effort being focused on finding alternative LPE methods and excellent progress has been made in the production of solution processable phosphorene . Recently, we used a microwave based approach to exfoliate the BP to obtain high‐quality, few‐layer BP sheets which showed exceptional stability .…”

“…These issues have led to significant effort being focused on finding alternative LPE methods and excellent progress has been made in the production of solution processable phosphorene . Recently, we used a microwave based approach to exfoliate the BP to obtain high‐quality, few‐layer BP sheets which showed exceptional stability . However, the solvent used was a high boiling solvent that is not compatible with many applications.…”

Black Phosphorus: Synthesis and Application for Solar Cells

“…d,e) Reproduced with permission. [37] l,m) HR-TEM of BPQDs with different lattice fringes. f) Cross-sectional TEM and g) HR-TEM image with selected area electron diffraction pattern (inset) of BP thin films prepared using PLD.…”