Tunable luminescence based on structural regulation in organic antimony halides for X-ray scintillation

Abstract

Organic antimony halides show high photoluminescence quantum yield (PLQY) due to their compositional and structural tunability, which provides the possibility for developing high quantum yield scintillators. Herein two antimony halides with the general formulae (NYP)₂SbCl₅ and (NYP)₂Sb₂Cl₈ (NYP = (naphthalene-1-ylmethyl) triphenylphosphine chloride, C₂₉H₂₄PCl) were successfully synthesized. The (NYP)₂Sb₂Cl₈ compound assumes a seesaw dimer [Sb₂Cl₈]²⁻ geometry, with the highest PLQY value of 19.34% among all known Sb₂Cl₈-types. The (NYP)₂SbCl₅ compound assumes a square pyramidal [SbCl₅]²⁻ geometry with a PLQY of approximately 75.07%. Furthermore, both components exhibit remarkable thermal and air stability. Under X-ray excitation, the high photo-quantum yield and negligible self-absorption enable (NYP)₂SbCl₅ to exhibit impressive scintillation performance. Its light yield is approximately 21 500 photons per MeV and its detection limit is as low as 757.51 nGy_air s⁻¹. The flexible scintillation screen of (NYP)₂SbCl₅ enables a high X-ray imaging resolution of 7.77 lp mm⁻¹ with great potential in practical X-ray imaging applications. This study not only reveals the correlation between the high-performance luminescence properties and crystal structure of organic antimony halides but also underscores the promising application prospects of the materials in the field of radiation detection.