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。

过渡金属硫族化合物及其范德华异质结在光电探测方面具有重要的应用前景。近年来，基于光电导效应、光诱导栅控效应、光伏效应、光-热电效应等机理的器件被提出并广泛研究。其中，基于光诱导栅控效应的过渡金属硫族化合物平面型光电器件因其与晶体管相近的器件结构、工艺兼容性以及较高的光电探测响应率而备受关注，然而往往存在响应速度慢、不施加栅压时暗电流大等缺点，制约了器件性能的进一步提升。因此，针对过渡金属硫族化合物光诱导栅控型光电器件，如何提高其响应速度、降低暗电流成为亟需解决的重要问题。该研究通过实验构建石墨烯/MoS₂/h-BN/石墨烯垂直异质结构，在传统石墨烯/MoS₂异质结中插入宽禁带h-BN势垒层以抑制器件暗电流，同时利用光照条件下光生载流子的FN隧穿效应提升器件的光电响应速度。该研究成功实现了皮安量级的暗电流以及相对较快的光电探测响应速度（响应时间约为0.3 s），相比于传统石墨烯/MoS₂异质结器件（响应时间约为20 s）有近两个数量级的提升，同时验证了基于FN隧穿效应的范德华垂直异质结构对于增强光电探测性能的积极作用。

考虑外加磁场导致的量子化朗道能级以及邻近效应诱导产生的交换作用，采用无规相近似（Random-phase approximation，RPA）下的介电函数对单层二硫化钼（Monolayer molybdenum disulfide，ML-MoS₂）的纵向磁光电导率进行理论研究。探究了磁场、邻近效应诱导产生的交换作用等因素对纵向磁光电导率的影响。在太赫兹（Terahertz，THz）频段，可以看到由导带内电子跃迁所贡献的两个磁光吸收峰。在可见光频段，可以观察到从价带到导带电子跃迁所贡献的多个磁光吸收峰。研究结果表明，邻近效应诱导产生的交换作用和磁场强度对纵向磁光电导率有重要的影响，单层二硫化钼可应用于可见光到太赫兹频段的自旋电子学和谷电子学磁光器件。

The human visual system, dependent on retinal cells, can be regarded as a complex combination of optical system and nervous system. Artificial retinal system could mimic the sensing and processing function of human eyes. Optically stimulated synaptic devices could serve as the building blocks for artificial retinas and subsequent information transmission system to brain. Herein, photonic synaptic transistors based on polycrystalline MoS₂, which could simulate human visual perception and brain storage, are presented. Moreover, the photodetection range from visible light to near-infrared light of MoS₂ multilayer could extend human eyes’ vision limitation to near-infrared light. Additionally, the photonic synaptic transistor shows an ultrafast speed within 5 μs and ultralow power consumption under optical stimuli about 40 aJ, several orders of magnitude lower than biological synapses (50 ms and 10 fJ). Furthermore, the backgate control could act as emotional modulation of the artificial brain to enhance or suppress memory function, i.e. the intensity of photoresponse. The proposed carrier trapping/detrapping as the main working mechanism is presented for the device. In addition, synaptic functionalities including short synaptic plasticity, long synaptic plasticity and paired-pulse facilitation could be successfully simulated based on the prepared device. Furthermore, the large difference between short synaptic plasticity and long synaptic plasticity reveals the better image pre-processing function of the prepared photonic synapses. The classical Pavlovian conditioning associated with the associative learning is successfully implemented as well. Therefore, the efficient and rich functionalities demonstrate the potential of the MoS₂ synaptic device that integrates sensing-memory-preprocessing capabilities for realizing artificial neural networks with different emotions that mimic human retina and brain.The human visual system, dependent on retinal cells, can be regarded as a complex combination of optical system and nervous system. Artificial retinal system could mimic the sensing and processing function of human eyes. Optically stimulated synaptic devices could serve as the building blocks for artificial retinas and subsequent information transmission system to brain. Herein, photonic synaptic transistors based on polycrystalline MoS₂, which could simulate human visual perception and brain storage, are presented. Moreover, the photodetection range from visible light to near-infrared light of MoS₂ multilayer could extend human eyes’ vision limitation to near-infrared light. Additionally, the photonic synaptic transistor shows an ultrafast speed within 5 μs and ultralow power consumption under optical stimuli about 40 aJ, several orders of magnitude lower than biological synapses (50 ms and 10 fJ). Furthermore, the backgate control could act as emotional modulation of the artificial brain to enhance or suppress memory function, i.e. the intensity of photoresponse. The proposed carrier trapping/detrapping as the main working mechanism is presented for the device. In addition, synaptic functionalities including short synaptic plasticity, long synaptic plasticity and paired-pulse facilitation could be successfully simulated based on the prepared device. Furthermore, the large difference between short synaptic plasticity and long synaptic plasticity reveals the better image pre-processing function of the prepared photonic synapses. The classical Pavlovian conditioning associated with the associative learning is successfully implemented as well. Therefore, the efficient and rich functionalities demonstrate the potential of the MoS₂ synaptic device that integrates sensing-memory-preprocessing capabilities for realizing artificial neural networks with different emotions that mimic human retina and brain.