浓度对电荷转移诱导的表面增强拉曼光谱的影响

Effect of concentration on surface-enhanced raman spectroscopy by charge transfer

银溶胶中加入具有双官能团的对氨基苯甲酸分子,功能分子PABA吸附到银粒子上形成Ag-PABA复合物,采用1064nm激发光对复合物进行SERS研究。研究发现,功能分子浓度较低时,b2振动得到极大增强,这是通过功能分子在银纳米粒子间电荷转移的直接结果。浓度较高时,SERS中a1振动占主导地位,因为在这样的体系中,银粒子被功能分子包围,彼此相距较远,跨越粒子的电荷转移被阻断的结果。

Complex PABA-Agsol were fabricated when p-aminobenzoic acid with double functional groups were added in silver colloid , and were investigated by surface-enhanced Raman spectroscopy with a 1064nm excitation. SERS results demonstrated that b2 vibration was greatly enhanced as the PABA concentration was lower, this may be the result of charge transfer of functional molecular between silver nanoparticles , while the concentration was higher , al vibration dominated in SERS spectra, because silver particles were surrounded by functional molecular, by which the particles are far away from each other and the charge transfer between the particles was blocked.