Lighting Hidden Traces: Rapid Green Synthesis of Zero-Dimensional Manganese Halide Perovskite for X-Ray and Fingerprint Imaging.

Lead-free, eco-friendly organic-inorganic manganese halides (OIMnHs) have attracted considerable attention for optoelectronic applications, owing to their outstanding optical properties and facile solution processability. Here, we present a novel zero-dimensional (0D) OIMnH, (BrEtPPh3)2MnBr4, synthesized as centimeter-sized single crystals (SCs) under ambient conditions. Additionally, we developed a rapid (<2 min) green "shake-and-make" synthesis method to directly obtain its powder form, named direct synthesized powder (DSP). Both SCs and DSP display strong green emission, with high photoluminescence quantum yields (PLQYs) of 51.28% for SCs and 88.68% for DSP, as well as exceptional color purity and photochemical stability. Flexible scintillator films, fabricated by blending PMMA with either SC or DSP, enable high-resolution X-ray imaging (5 lp/mm) and the imaging of diverse objects. Notably, DSP demonstrates a high light yield (∼117k photons/MeV), rivalling commercial and other Mn-based SC scintillators, and stands as the first lead-free, flexible perovskite scintillator made directly from powder. Furthermore, DSP facilitates efficient, sensitive, and background-free latent fingerprint detection, offering clear ridge detail, the resolution of levels 1-3 features, and strong contrast across various surfaces, even after aging. This study marks the first such demonstration for OIMnHs, underscoring a simple, eco-friendly approach to multifunctional materials for X-ray scintillation and forensic latent fingerprint detection.