Photoluminescent detection of lead dust in gunshot residue

Gunshot residue (GSR) analysis is essential for the forensic investigation of shooting incidents, but oftentimes still slow, cumbersome, and with limited spatial resolution. We here introduce a photoluminescent gunshot residue analysis (PL-Pb) for instant spatially resolved detection of GSR with high resolution. Lead dust in GSR reacts into a lead halide perovskite semiconductor that emits bright green light under ultraviolet irradiation. The sensitivity of PL-Pb enables straightforward detection of trace amounts of GSR from ricochet markings, bullet holes and combustion plumes. We show that GSR is transferable with high spatial resolution and preservation of fine details such as the polygonal patterns caused by the rifling of the pistol. Moreover, PL-Pb detection yields reproducible GSR patterns for shooting distance reconstruction series. We also show that the sensitivity and instant results make PL-Pb suitable for rapid presumptive testing of shooting suspects. Surprisingly, even after washing, we can still detect GSR on the hands of shooters, and we find GSR in a simple and straightforward manner on clothes, shoes, and other objects relevant to a shooting incident. Collectively, the instant results and sensitivity of PL-Pb opens unprecedented opportunities for (on-site) forensic investigations and highlights the potential of perovskite-based lead detection methods for lead containing, crime related micro-traces and lead dust in general.