Boric Acid-Derived Carbon Dot Scintillators for X-ray Imaging

Conventional carbon dots (CDs) exhibit negligible radioluminescence (RL) under ambient conditions, precluding their use in X-ray detection. Herein, we overturn this limitation with a metal-free CD scintillator engineered via synergistic matrix rigidification and defect engineering, achieved by compositing methoxyquinoline derivatives with boric acid (BA). The B₂O₃ rigid matrix derived from BA pyrolysis effectively suppresses molecular vibrations and introduces oxygen-vacancy channels of CDs, endowing photoluminescence quantum yield reaching 43.92% and low detection limit of 107 nGy s^-1. The materials retain >90% intensity after 90 cycles at 298 μGy s^-1 and can be operated up to 180 °C. Biocompatibility assessments show favorable hemocompatibility and cytocompatibility. In 3D printed vessels and tumor phantoms, the CD-based scintillation film furnishes real-time X-ray visualization of iohexol flow and laser-ablation margins with 0.8 mm spatial resolution, validating its translational potential for low-dose, image-guided interventions. This work provides a metal-free CD scintillator platform for dynamic imaging and real-time radiation detection.