Spectroscopic analysis of spin coated PVA/SWCNT/CuPc nanohybrid films and vapor sensing of DMMP

This study aims to fabricate and investigate nanohybrid films based on poly (vinyl alcohol) (PVA), single-walled carbon nanotubes (SWCNTs), and copper phthalocyanine (CuPc) for optical and DMMP vapor sensing applications. The films were prepared on ITO substrates via spin-coating with different compositions, including pure PVA, PVA/12.5% SWCNT/12.5% CuPc, PVA/18.7% SWCNT/25% CuPc, and PVA/25% SWCNT/50% CuPc. The effect of varying SWCNT/CuPc ratios on the optical and sensing properties was systematically studied. FTIR analysis confirmed the presence of π-π interactions and hydrogen bonding between PVA, SWCNTs, and CuPc. Optical measurements revealed a decrease in the band gap from 5.1 eV for pure PVA to 3.5–3.7 eV (B-band) and 2.2–2.8 eV (Q-band) for nanohybrid films. Raman spectra exhibited characteristic D and G bands in the range of 1349–1442 cm−1. The results showed that the incorporation of SWCNTs significantly enhanced DMMP vapor sensing performance in the range of 1–35 ppm due to improved conductivity. These findings demonstrate that the developed nanohybrid films are promising candidates for high-performance chemical vapor sensing applications.