Suppressed Concentration Quenching Via Divalent Eu/Sr Alloying in Hybrid Iodides Scintillators Toward Bright Luminescence for X‐ray Imaging
Lihan Chen, Shuai Zhang, Yuzhen Wang, Liang Li, Dongdan Chen, Kai Han, Zhiguo Xia
Abstract
Abstract Overcoming concentration quenching in rare‐earth‐activated luminescent materials always remains a challenge for enhancing photoluminescence quantum yield (PLQY). Herein, we report two divalent Sr‐based hybrid iodides, (Ph 3 MeP)SrI 3 and (Ph 3 EtP)SrI 3 (Ph 3 MeP = methyltriphenylphosphonium, Ph 3 EtP = ethyltriphenylphosphonium), and equivalent Eu/Sr alloying have been identified experimentally in the full range of 0 ≤ x ≤ 1 for (Ph 3 MeP)Sr (1‐ x ) Eu x I 3 and (Ph 3 EtP)Sr (1‐ x ) Eu x I 3 . These Eu/Sr‐based hybrid iodides exhibit 1D [Sr (1‐ x ) Eu x I 6 ] 4− octahedra chains, suppressing nonradiative energy loss effectively by maintaining optimal spacing and dispersion between adjacent Eu(II) emission centers. Upon even heavily Eu(II) alloying, (Ph 3 MeP)Sr 0.5 Eu 0.5 I 3 exhibits efficient green emission ( λ em = 525 nm) with a high PLQY of ∼92.2%. Accordingly, it achieves a high scintillation light yield of 54 000 ± 300 ph MeV −1 and a low detection limit of 49.9 nGy s −1 . Furthermore, ceramic wafers counterparts of Eu/Sr alloy prepared via cold sintering process demonstrate high‐resolution X‐ray imaging with a spatial resolution up to 15.7 lp mm −1 . These findings not only present a new family of hybrid bimetallic iodides via Eu/Sr alloying, but also provides structurally guided strategy to suppress concentration quenching toward bright luminescence for scintillation applications.