Self-assembled perylene diimide and naphthalene diimide Langmuir-Blodgett composite films with phthalocyanine for chemical gas sensing and SERS

In this research, Langmuir-Blodgett (LB) composite films were fabricated by integrating phthalocyanine (Pc) with derivatives of perylene diimide (PDI) and naphthalene diimide (NDI). The potential applications of these films in chemical gas sensing and surface-enhanced Raman spectroscopy (SERS) were investigated. The LB technique enables precise regulation of molecular arrangements within films, rendering them highly effective for applications as sensitive sensors. Upon exposure to NH₃ and HCl gases, the composite films exhibited good sensitivity, demonstrating their potential in chemical sensing applications. By employing R6G as a probe molecule, the films demonstrated remarkable SERS performance, distinguished by their uniformity, reproducibility, and amplified signal intensity, achieving an enhancement factor (EF) of 1.76 × 10⁵. This work demonstrates rapid colorimetric response to NH₃/HCl and achieves a high SERS enhancement factor of 1.76 × 10⁵, confirming the significant potential of these LB films for real-world sensing applications.