Langmuir-Blodgett composite films of amphiphilic perylene diimide and naphthalene diimide derivatives for acid-base gas sensing and surface-enhanced Raman scattering

In recent years, nanomaterials have garnered significant attention from both academic and industrial sectors owing to their exceptional properties and diverse application potential. In this context, the Langmuir-Blodgett (LB) technique, as an efficient self-assembly method, has been widely used for the preparation of functional thin films. Based on this, in this work, thin films based on perylene diimide (PDI) and naphthalene diimide (NDI) derivatives composites with dyes were successfully prepared using the LB technique and tested for their performance in gas sensing and Surface-Enhanced Raman Scattering (SERS). The experimental results show that the composite films have excellent response in acid-base gas sensing, especially in the CR dye subphase, and the PDI/CR and NDI/CR composite films are sensitive to HCl and NH 3 gases, with the NDI/CR composite films showing the most sensitive performance. In addition, the PDI/RhB 40-layer composite membranes exhibited significant SERS of R6G molecules with an enhancement factor as high as 3.94 × 10 5 , which is superior to many similar materials. The results presented herein demonstrate the substantial potential of LB technology in the development of multifunctional thin-film devices and its application in gas sensing and SERS.