In-situ formation of oleic acid amide ligand boosts persistent luminescence of zinc gallate nanoparticles toward efficient latent fingermark detection

Cr 3+ -doped zinc gallate (ZnGa 2 O 4 :Cr 3+ , ZGOC) nanomaterials feature with near-infrared emission and long afterglow properties. However, simultaneously controlling nanoparticle size and afterglow performance of ZGOC remains very challenging. A novel organic amine-stimulated solvothermal synthesis method for preparing ZGOC nanoparticles was demonstrated in this paper. Controllable synthesis of ZGOC nanoparticles was realized for uniform particle size distribution and excellent afterglow properties via adding different amines in organic phase system. Among them, by the triethylamine-stimulated solvothermal method, ZGOC nanoparticles are subsphaeroidal and narrow size distributed with an average particle size of about 11 nm. The near-infrared luminescence intensity of the nanoparticles was enhanced more than 7 times. The underneath organic amines stimulation mechanism was clarified as the in-situ formation of oleic acid amide ligand, consequently, enhancing the afterglow properties via combination results of surface defects passivation and ligand antenna effect. Furthermore, uniform particle size distribution and excellent afterglow properties make the prepared nanoparticles show great visualization in latent fingermark detection. The current finding of in-situ formation of oleic acid amide ligand offers guidance for the controllable synthesis of nanoparticles by the organic amines-stimulated solvothermal method.