State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
Shenzhen Geim Graphene Center, Tsinghua-Berkeley Shenzhen Institute and Institute of Materials Research, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
Nat Commun. 2023 May 11;14(1):2717. doi: 10.1038/s41467-023-38198-x.
Developing efficient noble-metal-free surface-enhanced Raman scattering (SERS) substrates and unveiling the underlying mechanism is crucial for ultrasensitive molecular sensing. Herein, we report a facile synthesis of mixed-dimensional heterostructures via oxygen plasma treatments of two-dimensional (2D) materials. As a proof-of-concept, 1D/2D WO/WSe heterostructures with good controllability and reproducibility are synthesized, in which 1D WO nanowire patterns are laterally arranged along the three-fold symmetric directions of 2D WSe. The WO/WSe heterostructures exhibited high molecular sensitivity, with a limit of detection of 5 × 10M and an enhancement factor of 5.0 × 10 for methylene blue molecules, even in mixed solutions. We associate the ultrasensitive performance to the efficient charge transfer induced by the unique structures of 1D WO nanowires and the effective interlayer coupling of the heterostructures. We observed a charge transfer timescale of around 1.0 picosecond via ultrafast transient spectroscopy. Our work provides an alternative strategy for the synthesis of 1D nanostructures from 2D materials and offers insights on the role of ultrafast charge transfer mechanisms in plasmon-free SERS-based molecular sensing.
开发高效的无贵金属表面增强拉曼散射（SERS）基底，并揭示其潜在机制，对于超灵敏分子传感至关重要。本文通过二维（2D）材料的氧等离子体处理，报道了一种简便的混合维度异质结构的合成方法。作为一个概念验证，我们合成了具有良好可控性和重现性的 1D/2D WO/WSe 异质结构，其中 1D WO 纳米线图案沿二维 WSe 的三重对称方向横向排列。WO/WSe 异质结构表现出较高的分子灵敏度，对亚甲蓝分子的检测限低至 5×10-7 M，增强因子高达 5.0×10，即使在混合溶液中也是如此。我们将超灵敏性能归因于 1D WO 纳米线独特结构引起的有效电荷转移和异质结构的有效层间耦合。通过超快瞬态光谱，我们观察到约 1.0 皮秒的电荷转移时间尺度。我们的工作为从二维材料合成一维纳米结构提供了一种替代策略，并深入了解了无等离子体 SERS 分子传感中超快电荷转移机制的作用。
