Amorphous Copper‐Based Nanoparticles with Clusterization‐Triggered Phosphorescence for Ultrasensing 2,4,6‐Trinitrotoluene

Abstract Amorphous metal‐based nanostructures have attracted great attention recently due to their facilitative electron transfer and abundant reactive sites, whereas it remains enigmatic as to whether amorphous copper‐based nanoparticles (CuNPs) can be achieved. Here, for synthesizing amorphous CuNPs, glutathione is adopted as a ligand to inhibit the nucleation and crystallization process via its electrostatic repulsion. By subtly tailoring the solvent polarity, not only can amorphous glutathione‐functionalized CuNPs (GSH‐CuNPs) with phosphorescent performance be achieved after transferring the non‐conjugation of GSH ligand to through‐space conjugation, namely clusterization‐triggered emission, but also the phosphorescence‐off of GSH‐CuNPs toward 2,4,6‐trinitrotoluene (TNT) can be realized by the photoinduced electron‐transfer process through the hydrogen bond channel, which is established between carboxyl and amino groups of GSH‐CuNPs with the nitryl group of TNT. Benefitting from the intrinsic superiorities of the amorphous CuNPs, desired phosphorescence and detection performances of GSH‐CuNPs toward airborne TNT microparticulates are undoubtedly realized, including high quantum yield (13.22%), excellent specificity in 33 potential interferents, instantaneous response, and ultralow detection limit (1.56 pg). The present GSH‐CuNPs are expected to stretch amorphous metal‐based nanostructures and deepen the insights into amorphous materials for optical detection.