基于超强拉曼增强金纳米粒子修饰的过渡金属双硫属化合物纳米片的分子检测（英文）

Ultrastrong Raman Enhancement on Gold Nanoparticle-Decorated Transition Metal Dichalcogenides Nanosheets for Molecule Detection

本文报道用不同尺寸的金纳米粒子(AuNPs)来修饰单层WS2和MoS2纳米片,通过表面增强拉曼散射(SERS)技术检测微量的罗丹明6G染料,并对比了它们在不同波长的激光激发下的等离子体特性。AuNPs在WS2和MoS2纳米片上的均匀沉积是通过种子介导的生长方法还原HAuCl4来实现的。我们进一步使用扫描电子显微镜和拉曼光谱对所制备的异质结构进行了表征。几种优化结构的拉曼增强因子接近108,几乎达到检测单分子需要的灵敏度。我们的研究结果表明,通过贵金属纳米粒子对超薄过渡金属双硫属元素化合物进行可控修饰是完全可行的。这个策略也适合于制备高效且灵活的基底,用在新一代基于表面增强拉曼散射的化学传感器和生物传感器上。Jason D Orlando 1,Ethan Kahn 2,Cindy Y Wong 3,Yin-ting Yeh 4,5,Tej B Limbu 1,Basant Chitara 1,Ana L Elias 4,5,Mauricio Terrones 4,5,YAN Fei(1.Department of Chemistry and Biochemistry,North Carolina Central University,Durham,NC.27707,USA;2.Department of Materials Science and Engineering,The Pennsylvania State University,University Park,PA.16802,USA;3.School for Engineering of Matter,Transport and Energy,Arizona State University,Tempe,AZ.85287,USA;4.Department of Physics,The Pennsylvania State University,University Park,PA.16802,USA;5.Center for Nanoscale Science,The Pennsylvania State University,University Park,PA.16802,USA)

A facile approach was developed for the decoration of monolayer tungsten disulfide(WS2) and molybdenum disulfide(MoS2) nanosheets with uniform gold nanoparticles with precisely controlled sizes,and their plasmonic properties were examined at different laser excitation wavelengths for trace detection of Rhodamine 6 G(R6 G) using surface-enhanced Raman scattering(SERS).Homogeneous deposition of gold nanoparticles on WS2 and MoS2 nanosheets was achieved by the reduction of hydrogen tetrachloroaurate via a seed-mediated growth method.The as-prepared heterostructures were characterized using scanning electron microscopy and Raman spectroscopy.Several substrates exhibited a Raman enhancement factor on the order of ~108,which is almost sufficient for the detection of single molecule.Our results demonstrate that controlled decoration of noble metal nanoparticles is a feasible and general strategy for structural modification of ultrathin transition metal dichalcogenides to develop highly-efficient and flexible substrates for next generation of SERS-based chemical and biological sensors.