Laiying Jing,Yiran Wang,Gang Lian,Baitao Zhang,Deliang Cui,Jingliang He,Qilong Wang,Ching-Ping Wong
2D van der Waals (VDWs) heterostructures have attracted much attention due to their exotic electronic and optical properties, which provide a new platform for material science and device fabrication. In this work, by coupling atomic interface engineering, an alternately intercalated superstructure of carbon and MoS 2 monolayers (m-C/MoS 2 ) is designed as a novel saturable absorber (SA) for mode-locked ultrafast laser generation. The novel intercalated structures exhibit excellent properties including wide bandgap, fast inter- and intra-band carrier relaxation time, and superior saturable absorption characteristic, etc. Consequently, a continuous wave mode-locked Yb:CALGO bulk laser with pulse width as short as 92 fs is achieved by using the prepared m-C/MoS 2 SA mirror, which is much shorter than those obtained with other reported 2D materials. This study provides a valuable strategy for the development of ultrashort pulse femtosecond lasers. The novel VDWs heterostructures also open new avenues toward advanced photonic devices.
Yuting Zhang,Lin Zhu,Hongqiang Xu,Qian Wu,Haojie Duan,Boshi Chen,Haiyong He
Potassium-ion batteries (PIBs) have aroused a large amount of interest recently due to the plentiful potassium resource, which may show cost benefits over lithium-ion batteries (LIBs). However, the huge volume expansion induced by the intercalation of large-sized potassium ions and the intrinsic sluggish kinetics of the anode hamper the application of PIBs. Herein, by rational design, nano-roses assembled from petals with a MoS2/monolayer carbon (C-MoS2) sandwiched structure were successfully synthesized. The interlayer distance of ultrathin C-MoS2was expanded from original MoS2of 6.2 to 9.6 Å due to the formation of the MoS2-carbon inter overlapped superstructure. This unique structure efficiently alleviates the mechanical strain, prevents the aggregation of MoS2, creates more active sites, facilitates electron transport, and enhances the specific capacity and K+diffusion kinetics. As a result, the prepared C-MoS2-1 anode delivers a high reversible specific capacity (437 mAh g−1at 0.1 A g−1) and satisfying rate performance (123 mAh g−1at 6.4 A g−1). Therefore, this work provides new insights into the design of high-performance anode materials of PIBs.Keywords:potassium-ion batteries;anode;layered 2D materials;transition-metal dichalcogenides;MoS2
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