Microwave-assisted rapid preparation of ZnS nanosphere for latent fingerprint detection and anti-counterfeiting applications

In the recent years, rare-earth free (REF) nanoscale phosphors have become a crucial basis in conventional lighting and display applications due to their low cost and availability. To explore the performance of such REF phosphors beyond its conventional applications in this work we have synthesised highly luminescent cubic phase zinc sulphide (ZnS) nanosphere via a facile, rapid and energy efficient microwave synthesis route and effectively applied for several exotic applications. Under 350 nm UV excitation, the synthesized nanophosphor exhibits intense green emission around 550 nm. The homogeneous spherical structure of the nanophosphor, with an average particle size of 20 nm, increases emission efficiency and leads to durable green emission. The obtained nanophosphor offers new opportunities for visualizing latent fingerprints (LFPs) on different surfaces via powder dusting technique. We further successfully demonstrate a high-performance security ink using this REF nanophosphorto prevent counterfeiting.