Porous carbon film/WO3-x nanosheets based SERS substrate combined with deep learning technique for molecule detection

•A non-noble-metal based novel SERS substrate-porous carbon film/WO3-x nanosheets was developed;•Detection limit of 10-7 M with the Raman enhancement factor of 106 was achieved on the optical substrate.•A deep leaning method was used to accurately analyze the Raman spectra of flavonoids of quercetin, 3-hydroxyflavone and flavone.•Quercetin can be accurately detected by the fully convolutional network, and lowest detectable concentration of 10-5 M was achieved.