Chemical gas sensor, surface enhanced Raman scattering and photoelectrics of composite Langmuir-Blodgett films consisting of polypeptide and dye molecules

Langmuir-Blodgett (LB) technology has attracted increasing interest to generate intelligent biomaterials combined with novel peptide molecules. In this work, the composite films based on palmitoyl pentapeptide-4 (PP4) and phthalocyanine dye molecules were prepared by LB technique. The aggregation forms of phthalocyanine dye molecules and the structures/properties of composite films were studied. UV-Vis, FT-IR and SEM and other characterizations proved that the LB films are successfully composited, which may be due to the H-bonding, pi-pi stacking and electrostatic forces. Interestingly, the TPPS/PP4 LB films show excellent acid-alkali gas response. In addition, the surface-enhanced Raman scattering (SERS) demonstrate that the TsNiPc/PP4 LB film exhibits surface-enhancing properties for crystal violet (CV) molecules. Furthermore, the result demonstrate that the prepared LB films show good photocurrent generation efficiency. This work provides new clues for the preparation of self-assembled films and their applications as gas sensors, SERS and photoelectric device.