Self-assembled composite Langmuir-Blodgett films of carbon nanotubes: An approach to enhance surface-enhanced Raman scattering and photoelectric performance

Abstract

Self-assembly is a technique that utilizes non-covalent interactions between molecules to assemble into ordered nano-scale aggregates from disordered states. Langmuir-Blodgett (LB) technique is one of the commonly applied methods for constructing molecular assemblies at gas-liquid interfaces. In this study, a series of ordered composite films of amino-functionalized carbon nanotubes (MWCNTs-NH2) and different dye molecules were prepared using LB technique. The surface-enhanced Raman scattering (SERS) performance of MWCNTs-NH2/dye composite films was investigated. The experimental results showed that MWCNTs-NH2/Methylene blue (MB) composite film exhibited good SERS enhancement performance for Rhodamine 6 G (R6G) molecules with an enhanced factor (EF) of 2.16 × 105, and had certain repeatability and uniformity, making it suitable for the detection of trace molecule. The photoelectric conversion efficiency of MWCNTs-NH2/dye composite films were also explored. MWCNTs-NH2/MB composite film not only exhibited the highest photocurrent value but also had the smallest impedance compared with the other films, indicating that it had lower impedance, better carrier transport rate, and more stable performance. This work provides an effective method for fabricating the composite LB films based on the carbon nanotubes with great SERS and photoelectric conversion efficiency.