Adesoye Samuel, Al Abdullah Saqer, Nowlin Kyle, Dellinger Kristen
Department of Nanoengineering, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, 2907 E Gate City Blvd, Greensboro, NC 27401, USA.
Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, 2907 E Gate City Blvd, Greensboro, NC 27401, USA.
Nanomaterials (Basel). 2022 Oct 12;12(20):3564. doi: 10.3390/nano12203564.
Semiconductors have great potential as surface-enhanced Raman scattering (SERS) substrates due to their excellent physiochemical properties. However, they provide low signal enhancements relative to their plasmonic counterparts, which necessitates innovation in their synthesis and application. Substitutional atomic doping is proposed to improve SERS enhancement by controlling electronic properties, such as the band gap. In this work, zinc oxide (ZnO) nanoparticles were synthesized by co-precipitation and doped with magnesium (Mg) at concentrations ranging from 2-10%. Nanoparticle morphology and size were obtained by scanning electron microscopy (SEM). Elemental composition and chemical states were determined using X-ray photoelectron spectroscopy (XPS). Optical properties were obtained with a UV-vis spectrophotometer, while a Raman spectrometer was used to acquire Raman signal enhancements. Stability was assessed by UV-vis spectroscopy, while cytotoxicity was evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed that the absorption edge of Mg-doped ZnO nanoparticles was red-shifted compared to pure ZnO nanoparticles. The band gap decreased (3.3-3.01 eV) with increasing Mg doping, while the highest Raman enhancement was observed at 2% doping. No significant cytotoxic effects were observed at low concentrations (3-12 μg/mL). Overall, this study provides evidence for the tunability of ZnO substrates and may serve as a platform for applications in molecular biosensing.
半导体因其优异的物理化学性质，作为表面增强拉曼散射（SERS）衬底具有巨大潜力。然而，相对于其等离子体对应物，它们提供的信号增强较低，这就需要在其合成和应用方面进行创新。有人提出通过控制电子性质（如带隙）来进行替代原子掺杂，以提高SERS增强效果。在这项工作中，通过共沉淀法合成了氧化锌（ZnO）纳米颗粒，并以2 - 10%的浓度掺杂镁（Mg）。通过扫描电子显微镜（SEM）获得纳米颗粒的形态和尺寸。使用X射线光电子能谱（XPS）确定元素组成和化学状态。用紫外 - 可见分光光度计获得光学性质，同时使用拉曼光谱仪获取拉曼信号增强。通过紫外 - 可见光谱评估稳定性，而通过3 -（4,5 - 二甲基噻唑 - 2 - 基）- 2,5 - 二苯基四氮唑溴盐（MTT）测定法评估细胞毒性。结果表明，与纯ZnO纳米颗粒相比，Mg掺杂的ZnO纳米颗粒的吸收边缘发生了红移。随着Mg掺杂量的增加，带隙减小（从3.3 eV降至3.01 eV），而在2%掺杂时观察到最高的拉曼增强。在低浓度（3 - 12 μg/mL）下未观察到明显的细胞毒性作用。总体而言，本研究为ZnO衬底的可调性提供了证据，并可作为分子生物传感应用的平台。
