Department of Applied Physics , KTH-Royal Institute of Technology , 106 91 Stockholm , Sweden.
Laser and Optoelectronics Engineering Department , University of Technology , 10066 Baghdad , Iraq.
ACS Appl Mater Interfaces. 2018 Sep 12;10(36):30871-30878. doi: 10.1021/acsami.8b10076. Epub 2018 Aug 27.
Photoinduced enhanced Raman spectroscopy from a lithium niobate on insulator (LNOI)-silver nanoparticle template is demonstrated both by irradiating the template with 254 nm ultraviolet (UV) light before adding an analyte and before placing the substrate in the Raman system (substrate irradiation) and by irradiating the sample in the Raman system after adding the molecule (sample irradiation). The photoinduced enhancement enables up to an ∼sevenfold increase of the surface-enhanced Raman scattering signal strength of an analyte following substrate irradiation, whereas an ∼threefold enhancement above the surface-enhanced signal is obtained for sample irradiation. The photoinduced enhancement relaxes over the course of ∼10 h for a substrate irradiation duration of 150 min before returning to initial signal levels. The increase in Raman scattering intensity following UV irradiation is attributed to photoinduced charge transfer from the LNOI template to the analyte. New Raman bands are observed following UV irradiation, the appearance of which is suggestive of a photocatalytic reaction and highlight the potential of LNOI as a photoactive surface-enhanced Raman spectroscopy substrate.
通过在添加分析物之前和将基底放入拉曼系统之前用 254nm 紫外 (UV) 光照射锂铌酸锂绝缘体 (LNOI)-银纳米粒子模板，以及在添加分子后在拉曼系统中照射样品（样品照射），证明了来自 LNOI-银纳米粒子模板的光致增强拉曼光谱。在基底照射后，光致增强可使分析物的表面增强拉曼散射信号强度增加约七倍，而对于样品照射，则可获得高于表面增强信号的约三倍增强。对于基底照射持续 150 分钟的情况，光致增强在 10 小时的过程中逐渐减弱，然后恢复到初始信号水平。UV 照射后拉曼散射强度的增加归因于从 LNOI 模板到分析物的光致电荷转移。在 UV 照射后观察到新的拉曼带，其出现表明存在光催化反应，并突出了 LNOI 作为光活性表面增强拉曼光谱基底的潜力。
