Multidentate Anion [C ₆ H ₆ NO ₆ ] ³⁻ Coordinated Hybrid Bismuth Complex Single Crystal for Stable X‐Ray Detection With High Sensitivity

Abstract

ABSTRACT Replacing halides with pseudohalides is effective strategy to address the ion migration and corrosion issues in bismuth (Bi) halides. However, pseudohalides also suffer from weak single‐point bonding, and larger molecular size enhances electron localization that are unfavorable for carrier transport. Therefore, it is crucial to develop new ligand that both ensures structural stability and delivers excellent detection performance. Herein, we first designed a novel multidentate ligand, Nitrilotriacetate [N(CH 2 COO) 3 ] 3− (NTA), which forms (NH 4 ) 3 Bi(NTA) 2 through coordination with Bi. Theoretical calculations reveal that NTA coordination enhances the Bi─O bond, raising migration energies of Bi and O to 5.57 and 1.04 eV, which are significantly higher than those of Bi and I in (NH 4 ) 3 Bi 2 I 9 (1.94 and 0.42 eV). Furthermore, unlike in halide complex where the band edges are dominated by Bi and I atomic orbitals, the band edges of (NH 4 ) 3 Bi(NTA) 2 are primarily contributed by NTA molecular orbitals, and the hydrogen bond network (N─H···O) effectively links the individual NTA 3− , enhancing the carrier transport efficiency. Ultimately, (NH 4 ) 3 Bi(NTA) 2 ‐based device demonstrated ultralow limit of detection 24.83 nGy/s and high sensitivity (6116 µC Gy −1 cm −2 ), along with no obvious corrosion for electrodes. This work provides new approach to address the challenges of halide coordination complexes.