We demonstrate a flexible, low-cost, and highly reproducible hydrophobic surface-enhanced Raman scattering (SERS) substrate produced by inkjet printing silver nanoparticles (Ag NPs) on a commercial overhead projector (OHP) film. Unlike a conventional Raman substrate such as glass or a silicon wafer, the OHP film is flexible, is easy and safe to handle, and has extremely low fabrication cost. Furthermore, our inkjet printing method is suitable for large-area fabrication of well-defined functional nanostructures. The prepared SERS substrate is a nanoplasmonic material owing to the presence of Ag NPs with hydrophobic surfaces due to their being coated with stearic acid (SA). The SERS activities of the OHP@Ag and SA-coated OHP@Ag substrates were verified experimentally using rhodamine B (RhB) as an analyte. The Raman band intensities of RhB deposited on the OHP@Ag substrate suggested obvious enhancement compared with those of the OHP film without Ag NPs. The SA-coated OHP@Ag substrate showed two-fold signal enhancement compared to the hydrophilic OHP@Ag substrate because of the hydrophobic condensation effect. The SERS detection signal for RhB had a relative standard deviation of 4.4%, revealing the excellent repro-ducibility of the substrate. Thus, this cost-effective and hydrophobic SERS flexible substrate can be used widely in SERS-based detection.

中文翻译：

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通过银纳米粒子喷墨打印制造柔性、高度可重复和疏水的表面增强拉曼散射基板

我们展示了一种灵活、低成本且高度可重复的疏水性表面增强拉曼散射 (SERS) 基板，该基板通过在商业高架投影仪 (OHP) 胶片上喷墨打印银纳米粒子 (Ag NP) 产生。与传统的拉曼基板（如玻璃或硅晶片）不同，OHP 薄膜具有柔韧性，易于操作且安全，并且制造成本极低。此外，我们的喷墨打印方法适用于大面积制造定义明确的功能纳米结构。所制备的 SERS 基底是一种纳米等离子体材料，因为存在具有疏水表面的 Ag NP，因为它们被硬脂酸 (SA) 包覆。使用罗丹明 B (RhB) 作为分析物，通过实验验证了 OHP@Ag 和 SA 涂层的 OHP@Ag 基材的 SERS 活性。与没有 Ag NPs 的 OHP 薄膜相比，沉积在 OHP@Ag 衬底上的 RhB 的拉曼带强度表明明显增强。由于疏水缩合效应，SA 涂层的 OHP@Ag 基材与亲水性 OHP@Ag 基材相比显示出两倍的信号增强。RhB 的 SERS 检测信号的相对标准偏差为 4.4%，表明底物具有出色的重现性。因此，这种具有成本效益和疏水性的 SERS 柔性基板可广泛用于基于 SERS 的检测。RhB 的 SERS 检测信号的相对标准偏差为 4.4%，表明底物具有出色的重现性。因此，这种具有成本效益和疏水性的 SERS 柔性基板可广泛用于基于 SERS 的检测。RhB 的 SERS 检测信号的相对标准偏差为 4.4%，表明底物具有出色的重现性。因此，这种具有成本效益和疏水性的 SERS 柔性基板可广泛用于基于 SERS 的检测。