Molybdenum disulfide (MoS₂) is a notable two-dimensional (2D) transition metal dichalcogenide (TMD) with properties ideal for nanoelectronic and optoelectronic applications. With growing interest in the material, it is critical to understand its layer-number-dependent properties and develop strategies for controlling them. Here, we demonstrate a photo-modulation of MoS₂ flakes and elucidate layer-number-dependent charge transfer behaviors. We fabricated hybrid structures by functionalizing MoS₂ flakes with a uniform layer of photochromic diarylethene (DAE) molecules that can switch between closed- and open-form isomers under UV and visible light, respectively. We discovered that the closed-form DAE quenches the photoluminescence (PL) of monolayer MoS₂ when excited at 633 nm and that the PL fully recovers after DAE isomerization into the open-form. Similarly, the electric conductivity of monolayer MoS₂ is drastically enhanced when interacting with the closed-form isomers. In contrast, photoinduced isomerization did not modulate the properties of the hybrids made of MoS₂ bilayers and trilayers. Density functional theory (DFT) calculations revealed that a hole transfer from monolayer MoS₂ to the closed-form isomer took place due to energy level alignments, but such interactions were prohibited with open-form DAE. Computational results also indicated negligible charge transfer at the hybrid interfaces with bilayer and trilayer MoS₂. These findings highlight the critical role of layer-number-dependent interactions in MoS₂-DAE hybrids, offering valuable insights for the development of advanced photoswitchable devices.

中文翻译：

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2D MoS2-二芳烯杂化物中的层数依赖性光开关性


二硫化钼 （MoS₂） 是一种著名的二维 （2D） 过渡金属二硫化物 （TMD），具有理想的纳米电子和光电应用性能。随着人们对这种材料的兴趣日益浓厚，了解其与层数相关的特性并制定控制它们的策略至关重要。在这里，我们演示了 MoS₂ 薄片的光调制，并阐明了层数依赖性的电荷转移行为。我们通过将 MoS₂ 薄片与均匀的光致变色二芳烯 （DAE） 分子层功能化来制造杂化结构，该分子可以分别在紫外光和可见光下在封闭和开放形式的异构体之间切换。我们发现，当在 633 nm 处激发时，封闭式 DAE 会淬灭单层 MoS₂ 的光致发光 （PL），并且 PL 在 DAE 异构化成开放形式后完全恢复。同样，当与封闭型异构体相互作用时，单层 MoS₂ 的导电性会大大增强。相比之下，光诱导异构化不会调节由 MoS₂ 双层和三层制成的杂化物的性质。密度泛函理论 （DFT） 计算表明，由于能级对齐，发生了从单层 MoS₂ 到闭式异构体的空穴转移，但这种相互作用被开放型 DAE 禁止。计算结果还表明，在具有双层和三层 MoS₂ 的混合界面处的电荷转移可以忽略不计。 这些发现突出了层数依赖性相互作用在 MoS_2-DAE 杂化物中的关键作用，为开发先进的光开关器件提供了有价值的见解。