Robust Perovskite Polymer Scintillating Fibers Converted from Tennis Strings

Abstract Perovskite materials are emerging as next‐generation scintillators due to their strong light absorption, high light yield, fast response times, and solution‐processability. While single‐crystal perovskites offer excellent performance, their brittleness and environmental sensitivity hinder scalability. Perovskite nanoparticles provide a promising alternative but face challenges such as poor stability and aggregation, reducing scintillation efficiency. Embedding these nanoparticles in polymer matrices has been explored to improve stability, however, existing methods offer limited control over nanoparticle size and transparency, restrict polymer choice, and are incompatible with low‐swelling polymers like PET, which offer superior barrier properties and enhance stability. Here, these limitations are addressed using an optimized deep‐dyeing method that enables uniform incorporation of perovskite nanoparticles into PET fibers, a low‐swelling polymer previously inaccessible for composite scintillators. This approach yields transparent, color‐tunable, and thermally stable perovskite‐PET scintillating fibers suitable for scalable applications. The PET fibers used are sourced from commercially available tennis strings, offering a low‐cost, mechanically robust, and scalable platform for composite fabrication. The resulting fibers exhibit excellent photoluminescence and radioluminescence stability, full recovery after thermal cycling up to 167 °C, strong moisture resistance, and a high light yield of 23,000 photons/MeV, more than twice that of a commercial scintillating fiber. Their flexible geometry and small cross‐section allow integration into modular or wearable detection systems with high spatial resolution. Incorporating cladding layers in future designs can further enhance waveguiding and overall scintillator performance. These results highlight a scalable and versatile strategy for high‐performance scintillating fibers with broad potential in x‐ray imaging and dosimetry in harsh environments.