掺磷TiO2优化TiO2/MBA/Ag三明治结构的SERS性能

摘要

In this paper,P doping TiO2 were synthesized by using H3 PO4 as phosphorus source via a facile sol hydrothermal process,and silver nanoparticles were synthesized by Lee and Meisel method.We choose 4-Mercaptobenzoic acid(4-MBA)as the probe molecule to build TiO2/MBA/Ag sandwich structures as active substrates for surface-enhanced Raman scattering(SERS).The samples were characterized for morphology,struc ture,optical property and surface chemical composition by Transmission Electron Microscope(TEM),X-Ray Diffraction(XRD),X Ray Photoelectron Spectroscopy(XPS),UV-visible Diffuse Reflectance Spectra(DRS)and Raman spectroscopy.It shows that the crystal size of TiO2 was about 6 12 nm and P doping could not influence the phase of the crystal.XPS revealed that P5+ replace Ti4+ and doping into the crystal lattice by forming O-P O.The Raman result shows that P doped TiO2 has a higher intensity of Raman signals in P-TiO2/MBA/Ag sandwich structures than that in pure TiO2/MBA/Ag,the 1.77％ P-TiO2 own the strongest Raman signals than any other samples,this is due to phosphorus doping which narrow the energy band gap of TiO2 and abundant the surface states,these were profitable for TiO2 to MBA molecule charge transfer process.%本文以磷酸为磷源,通过溶胶水热法制备磷掺杂TiO2,利用Lee和Meisel的方法制备银溶胶,以4-巯基苯甲酸(MBA)为探针分子,通过构建TiO2/MBA/Ag三明治结构,研究磷掺杂二氧化钛对该基底表面增强拉曼(SERS)性能的提升.通过TEM、XRD、XPS、DRS和拉曼光谱图表征二氧化钛的形貌结构、化学组成、光学和拉曼性能,结果表明,制备出的磷掺杂二氧化钛为锐钛矿型纳米颗粒,粒径范围6～12 nm,XPS显示磷以p5-替代了Ti4-,形成O-P-O键掺入TiO2的晶格中,当磷的掺杂量在1.77％时,TiO2/MBA/Ag三明治体系具有最佳的SERS信号,这是因为适量的磷掺杂降低了TiO2的能带间隙,丰富TiO2的表面态,这能促进TiO2向MBA分子的电荷转移.