Improved Carrier Transport and Enhanced Stability through Defect Reduction via Zn ²⁺ Doping in 0D Hybrid Manganese Halides for X-ray Detectors

Zero-dimensional (0D) organic-inorganic hybrid manganese halides (OIHMnHs) have attracted attention in direct X-ray detection due to their low ionic mobility and high stability. However, the carrier transport and collection in 0D OIHMnHs are restricted by the isolated inorganic polyhedra, limiting their application in high-performance X-ray detectors. Accordingly, optimizing carrier transport properties to achieve high-performance 0D OIHMnH X-ray detectors remains both critically important and challenging. Herein, Zn²⁺ doping is implemented in 0D TMG₂MnBr₄ to synthesize TMG₂Mn_0.93Zn_0.07Br₄ and TMG₂ZnBr₄ (TMG = 1,1,3,3-tetramethylguanidine) single crystals. Density functional theory calculations indicate that the A-site cation dominates the conduction band minimum (CBM), forming multidimensional carrier transport pathways between inorganic polyhedra and organic cations. Zn²⁺ doped in the B site further strengthens cation-anion coupling interactions, suppresses ion migration, reduces defects, and improves charge extraction and transport. The resulting TMG₂Mn_0.93Zn_0.07Br₄ SC X-ray detector achieves a μτ product of 1.15 × 10^-3 cm² V^-1, a sensitivity of 8017 μC Gy_air^-1 cm^-2, a detection limit of 63.8 nGy_air s^-1, stable operation, and the demonstration of high-resolution X-ray imaging. This work provides a foundation for developing eco-friendly X-ray detectors with high sensitivity and low-dose detection capabilities for medical imaging and radiation detection applications.