SERS Detection of Trace Carcinogenic Aromatic Amines Based on Amorphous MoO₃ Monolayers

Aromatic amines are important commercial chemicals, but their carcinogenicity poses a threat to humans and other organisms, making their rapid quantitative detection increasingly urgent. Here, amorphous MoO₃ (a-MoO₃) monolayers with localized surface plasmon resonance (LSPR) effect in the visible region are designed for the trace detection of carcinogenic aromatic amine molecules. The hot-electron fast decay component of a-MoO₃ decreases from 301 fs to 150 fs after absorption with methyl orange (MO) molecules, indicating the plasmon-induced hot-electron transfer (PIHET) process from a-MoO₃ to MO. Therefore, a-MoO₃ monolayers present high SERS performance due to the synergistic effect of electromagnetic enhancement (EM) and PIHET, proposing the EM-PIHET synergistic mechanism in a-MoO₃. In addition, a-MoO₃ possesses higher electron delocalization and electronic state density than crystal MoO₃ (c-MoO₃), which is conducive to the PIHET. The limit of detection (LOD) for o-aminoazotoluene (o-AAT) is 10^-9 M with good uniformity, acid resistance, and thermal stability. In this work, trace detection and identification of various carcinogenic aromatic amines based on a-MoO₃ monolayers is realized, which is of great significance for reducing cancer infection rates.