通过γ射线辐照技术引入“自掺杂”缺陷，优化硬碳层间尺寸和孔结构。通过扫描电镜、X射线衍射、拉曼光谱、等温氮气吸脱附等方法探究了吸收剂量对硬碳层间距与内部缺陷、无序结构的影响；通过恒电流充/放电研究了材料的电化学性能。结果表明：较低剂量辐照会提升硬碳表面结晶度，而随着吸收剂量的增加，硬碳无序结构增多，辐照后硬碳电化学性能得到明显改善。在140 kGy剂量辐照下，硬碳呈现出425.343 m²/g的高比表面积，硬碳在30 mA/g能够提供300 mAh/g的储钠容量，在1 A/g大电流密度容量仍然保持在195 mAh/g，对比未辐照处理的硬碳，电极容量提高了3倍，并且在大倍率充/放电过程中保持优良的稳定性能。这项工作为设计先进的纳米材料及缺陷工程在储能领域的应用提供了新的途径和思路。

二硫化钼(MoS₂)作为水系锌离子电池的正极材料, 受到锌离子(Zn²⁺)与主体框架之间的强静电相互作用表现出缓慢的反应动力学。并且MoS₂的层间距较窄难以嵌入大尺寸水合Zn²⁺, 导致MoS₂电极呈现出较低的放电比容量。本研究通过一种简单的氨水辅助水热法制备了NH₄⁺扩层的二硫化钼(MoS₂-N)电极, 氨水分解产生的氨气在促进硫代乙酰胺水解和提供还原性S^2-的同时, 还会产生大量NH₄⁺作为插层离子, 将MoS₂的层间距由0.62 nm扩展至0.92 nm, 进而大大降低了Zn²⁺嵌入能垒(改性电极的电荷转移电阻R_ct低至35 Ω)。当电流密度为0.1 A·g^-1时, MoS₂-N电极的初始放电比容量相比未扩层的MoS₂电极提高了1倍, 高达149.9 mAh·g⁻¹。同时在1.0 A·g^-1电流密度下放电比容量稳定在110 mAh·g^-1左右, 循环200圈后库仑效率将近100%。本研究提出的氨水辅助扩层法, 丰富了提升MoS₂电化学性能的改性策略, 为后续的正极材料开发提供了新的思路。

Moiré materials, composed of two single-layer two-dimensional semiconductors, are important because they are good platforms for studying strongly correlated physics. Among them, moiré materials based on transition metal dichalcogenides (TMDs) have been intensively studied. The hetero-bilayer can support moiré interlayer excitons if there is a small twist angle or small lattice constant difference between the TMDs in the hetero-bilayer and form a type-II band alignment. The coupling of moiré interlayer excitons to cavity modes can induce exotic phenomena. Here, we review recent advances in the coupling of moiré interlayer excitons to cavities, and comment on the current difficulties and possible future research directions in this field.Moiré materials, composed of two single-layer two-dimensional semiconductors, are important because they are good platforms for studying strongly correlated physics. Among them, moiré materials based on transition metal dichalcogenides (TMDs) have been intensively studied. The hetero-bilayer can support moiré interlayer excitons if there is a small twist angle or small lattice constant difference between the TMDs in the hetero-bilayer and form a type-II band alignment. The coupling of moiré interlayer excitons to cavity modes can induce exotic phenomena. Here, we review recent advances in the coupling of moiré interlayer excitons to cavities, and comment on the current difficulties and possible future research directions in this field.

Two-dimensional (2D) semiconductors have captured broad interest as light emitters, due to their unique excitonic effects. These layer-blocks can be integrated through van der Waals assembly,i.e., fabricating homo- or heterojunctions, which show novel emission properties caused by interface engineering. In this review, we will first give an overview of the basic strategies that have been employed in interface engineering, including changing components, adjusting interlayer gap, and tuning twist angle. By modifying the interfacial factors, novel emission properties of emerging excitons are unveiled and discussed. Generally, well-tailored interfacial energy transfer and charge transfer within a 2D heterostructure cause static modulation of the brightness of intralayer excitons. As a special case, dynamically correlated dual-color emission in weakly-coupled bilayers will be introduced, which originates from intermittent interlayer charge transfer. For homobilayers and type Ⅱ heterobilayers, interlayer excitons with electrons and holes residing in neighboring layers are another important topic in this review. Moreover, the overlap of two crystal lattices forms moiré patterns with a relatively large period, taking effect on intralayer and interlayer excitons. Particularly, theoretical and experimental progresses on spatially modulated moiré excitons with ultra-sharp linewidth and quantum emission properties will be highlighted. Moiré quantum emitter provides uniform and integratable arrays of single photon emitters that are previously inaccessible, which is essential in quantum many-body simulation and quantum information processing. Benefiting from the optically addressable spin and valley indices, 2D heterostructures have become an indispensable platform for investigating exciton physics, designing and integrating novel concept emitters.Two-dimensional (2D) semiconductors have captured broad interest as light emitters, due to their unique excitonic effects. These layer-blocks can be integrated through van der Waals assembly,i.e., fabricating homo- or heterojunctions, which show novel emission properties caused by interface engineering. In this review, we will first give an overview of the basic strategies that have been employed in interface engineering, including changing components, adjusting interlayer gap, and tuning twist angle. By modifying the interfacial factors, novel emission properties of emerging excitons are unveiled and discussed. Generally, well-tailored interfacial energy transfer and charge transfer within a 2D heterostructure cause static modulation of the brightness of intralayer excitons. As a special case, dynamically correlated dual-color emission in weakly-coupled bilayers will be introduced, which originates from intermittent interlayer charge transfer. For homobilayers and type Ⅱ heterobilayers, interlayer excitons with electrons and holes residing in neighboring layers are another important topic in this review. Moreover, the overlap of two crystal lattices forms moiré patterns with a relatively large period, taking effect on intralayer and interlayer excitons. Particularly, theoretical and experimental progresses on spatially modulated moiré excitons with ultra-sharp linewidth and quantum emission properties will be highlighted. Moiré quantum emitter provides uniform and integratable arrays of single photon emitters that are previously inaccessible, which is essential in quantum many-body simulation and quantum information processing. Benefiting from the optically addressable spin and valley indices, 2D heterostructures have become an indispensable platform for investigating exciton physics, designing and integrating novel concept emitters.

Mxenes以其优异的比表面积、高导电率和组分可调性而受到广泛研究, 并用作高效锂离子电池的电极材料。然而, 其有限的存储容量以及锂离子扩散引起的剧烈晶格膨胀限制了MXenes作为电极材料的应用。本研究设计了具有代表性的MXene材料卤化(氟化、氯化或溴化)-Ti₃C₂。采用基于密度泛函理论的范德瓦耳斯修正的第一性原理计算方法研究了表面端基(T=F^-、Cl^-和Br^-)修饰对锂离子电池中Ti₃C₂负极的原子结构、电学性质、力学性质以及电化学性能的影响。研究表明, Ti₃C₂T₂单层具有良好的结构稳定性、力学性质和导电性质。相比Ti₃C₂F₂和Ti₃C₂Br₂, Ti₃C₂Cl₂单层具有较大的弹性模量(沿二维薄膜两个方向的弹性模量分别为321.70和329.43 N/m)、较低的锂离子扩散势垒(0.275 eV)、开路电压(0.54 V)和较大的理论存储容量(化学计量比为Ti₃C₂Cl₂Li₆时达674.21 mA·h/g), 这表明Ti₃C₂Cl₂单层作为锂电池电极具有良好的安全稳定性和充放电速率。此外, 端基氯化扩大了层间距, 进而提高了Ti₃C₂Cl₂中锂离子的可穿透性和快速充放电速率。本研究表明, 表面氯化的Ti₃C₂纳米薄膜是一种很有前途的锂电池负极材料, 为其它的MXenes基电极材料设计与开发提供了重要的设计思路。