A Lead-Free Zero-Dimensional Mn-Sb Hybrid Halide Enabling Blue-Light-Driven Near-Infrared Emission and X-ray Imaging

Abstract

Broadband near-infrared (NIR) emitting materials hold significant promise for applications in night vision and biomedical imaging. However, their properties are still limited by issues such as complex structures and formation processes, high costs, limited photoluminescence quantum yields (PLQY), and the need for high excitation energy. In particular, achieving efficient and broadband NIR emission under blue-light excitation is still challenging for lead-free metal halide systems. Herein, Sb³⁺doped zero-dimensional (0D) [C₁₉H₁₈P]₂MnBr₄ crystals were synthesized via a facile room-temperature evaporation crystallization process using ethanol as a solvent, giving a green emission band. Sb³⁺ can be doped into this crystal to produce a broadband red/NIR emission centered at 705 nm. The NIR component originates from the triplet self-trapped exciton (STE) emission of Sb³⁺ as well as a minor Mn-Sb DAP contribution under 450 nm blue-light excitation. The material can be readily prepared on a large scale under ambient conditions and exhibits excellent environmental stability. By integrating (C₁₉H₁₈P)₂MnBr₄:6%Sb phosphors with a commercial blue LED chip, a high-performance NIR light-emitting diode (NIR-LED) was successfully fabricated, demonstrating clear bioimaging capability. Moreover, the material exhibits pronounced scintillation under X-ray irradiation, with a low detection limit of 57.67 nGyair s⁻¹ and a spatial resolution of 14 lp mm⁻¹. These results highlight its potential applications in night vision and biomedical imaging.