Chemical design of luminescent metal halides as high-performance X-ray scintillators is in urgent demand. Herein, rare earth Eu(II) was innovated as a B-site cation to create brand-new metal halide scintillators, and a regulating bandgap was further developed via organic molecule design based on the same anionic chain of [EuBr₃MeOH]_n^n–, namely, [Cat]EuBr₃MeOH [Cat = 1-butyl-1-methylpiperidinium (PP14), 1-propyl-1-methylpiperidinium (PP13), and 1-ethyl-3-methylimidazolium (Emim)]. Owing to the smaller bandgap of [Emim]Br, [Emim]EuBr₃MeOH possesses an enhanced light yield of 43,000 ± 100 ph MeV^–1 as scintillators. The conjugated attribute of Emim⁺ also contributes to π–π stacking, resulting in a more rigid structure, reducing the nonradiative transition. The scintillator film by using [Emim]EuBr₃MeOH emanates spatial resolution above 10 lp mm^–1. This study provides a design principle by B-site cations screening and bandgap engineering of organic cations for enhancing the light yield property and exemplifies novel materials in the family of Eu(II) halide hybrids as potential scintillators.

中文翻译：

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铕 (II) 基溴化物杂化物中的带隙变窄可改善 X 射线闪烁和成像

作为高性能 X 射线闪烁体的发光金属卤化物的化学设计是迫切需要的。在此，创新稀土Eu(II)作为B位阳离子，创造了全新的金属卤化物闪烁体，并基于[EuBr ₃ MeOH] _n ^{n相同的阴离子链，通过有机分子设计进一步开发了调节带隙–}，即 [Cat]EuBr ₃ MeOH [Cat = 1-丁基-1-甲基哌啶鎓 (PP14)、1-丙基-1-甲基哌啶鎓 (PP13) 和 1-乙基-3-甲基咪唑鎓 (Emim)]。由于[Emim]Br 的带隙较小，[Emim]EuBr _{3 MeOH 作为闪烁体具有 43,000 ± 100 ph MeV} ^–1的增强光产额。 Emim ⁺的共轭属性也有助于 π-π 堆叠，从而产生更刚性的结构，减少非辐射跃迁。使用[Emim]EuBr ₃ MeOH 的闪烁体薄膜发出的空间分辨率高于10 lp mm ^–1。这项研究提供了通过 B 位阳离子筛选和有机阳离子带隙工程来提高光输出性能的设计原理，并举例说明了 Eu(II) 卤化物杂化物家族中的新型材料作为潜在的闪烁体。