Two-dimensional (2D) material nanocomposites have emerged as a material system for discovering new physical phenomena and developing novel devices. However, because of the low density of states of most two-dimensional materials such as graphene, the heterostructure of nanocomposites suffers from an enhanced depletion region, which can greatly reduce the efficiency of the charge carrier transfer and deteriorate the device performance. To circumvent this difficulty, here we propose an alternative approach by inserting a second 2D mediator with a heavy effective mass having a large density of states in-between the heterojunction of 2D nanocomposites. The mediator can effectively reduce the depletion region and form a type-II band alignment, which can speed up the dissociation of electron–hole pairs and enhance charge carrier transfer. To illustrate the principle, we demonstrate a novel stretchable photodetector based on the combination of graphene/ReS₂/perovskite quantum dots. Two-dimensional ReS₂ acts as a mediator in-between highly absorbing perovskite quantum dots and a high-mobility graphene channel and a thiol-based linker between the ReS₂ and the perovskite. It is found that the optical sensitivity can be enhanced by 22 times. This enhancement was ascribed to the improvement of the charge transfer efficiency as evidenced by optical spectroscopy measurements. The produced photosensors are capable of reaching the highest reported value of photoresponsivity (>10⁷ A W^–1) and detectivity compared to previously studied stretchable devices. Mechanical robustness with tolerable strain up to 100% and excellent stability make our device ideal for future wearable electronics.

中文翻译：

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量子点/石墨烯异质结处的重质介体，用于有效的载流子转移：高性能光电器件的替代方法

二维（2D）材料纳米复合材料已经成为一种用于发现新的物理现象和开发新颖装置的材料系统。然而，由于诸如石墨烯的大多数二维材料的状态密度低，纳米复合材料的异质结构具有增大的耗尽区，这会大大降低电荷载流子转移的效率并降低器件性能。为了解决这一难题，在这里我们提出了一种替代方法，即在2D纳米复合材料的异质结之间插入有效质量大，质量高的第二个2D介体。介体可以有效地减少耗尽区并形成II型能带排列，从而可以加速电子-空穴对的离解并增强电荷载流子的转移。_2个/钙钛矿量子点。二维ReS ₂充当高吸收钙钛矿量子点与ReS ₂和钙钛矿之间的高迁移率石墨烯通道和基于硫醇的连接基之间的介体。发现光学灵敏度可以提高22倍。这种增强归因于电荷转移效率的提高，如光谱学测量所证明的。所生产的光电传感器能够达到最高的光响应报告值（> 10 ⁷ AW ^–1和先前研究过的可拉伸设备相比，其探测能力更强。具有高达100％的可承受应变的机械强度和出色的稳定性，使我们的设备成为未来可穿戴电子产品的理想选择。