Boosting Crystal Growth and Radioluminescence in Hybrid Cu(I) Halide Scintillators via Additive-Strengthened Ionic...

We herein address two fundamental challenges in rod-like ionic hybrid copper(I) halide scintillators-insufficient metal-to-ligand charge transfer leading to low radioluminescence efficiency, and anisotropic crystal growth that restricts the fabrication of large-area single-crystalline scintillator screen. Guided by computational insight, we introduce a "one stone, two birds" molecular strategy employing neutral 1,2-propanediamine (1,2-PDA) as a dual-function additive in C₆H₁₈N₂Cu₂I₄. Comprehensive mechanistic studies reveal that 1,2-PDA not only strengthens ionic interactions between organic ligand (C₆H₁₈N₂ ²⁺) and Cu(I) halide clusters, promoting oriented aggregation at crystal interfaces, but also induces significant lattice distortion upon defect incorporation, which enhances intersystem crossing and intensifies electron-phonon coupling, thereby boosting self-trapped exciton (STE) emission. This synergistic mechanism yields a 3-fold enhancement in photoluminescence quantum yield (PLQY: 17.53% to 52.96%) and a 2.77-fold enhancement in radioluminescence intensity. Moreover, we achieved a large-area single-crystalline film (≈10 × 7 × 0.31 mm³) demonstrates exceptional X-ray imaging resolution of 22.3 lp mm^-1. This approach demonstrates broad applicability across diverse hybrid metal halides, concurrently improving crystal dimensionality and scintillation performance, thus establishing a versatile molecular design rule for high-performance radiation detection materials.