Two-dimensional (2D) hybrid organic–inorganic perovskite (HOIP) crystals show promise as scintillating materials for wide-energy radiation detection, outperforming their three-dimensional counterparts. In this study, we synthesized single crystals of (PEA_2–xBZA_x)PbBr₄ (x ranging from 0.1 to 2), utilizing phenethylammonium (C₆H₅CH₂CH₂NH₃⁺) and benzylammonium (C₆H₅CH₂NH₃⁺) cations. These materials exhibit favorable optical and scintillation properties, rendering them suitable for high light yield (LY) and fast-response scintillators. Our investigation, employing various techniques such as X-ray diffraction (XRD), photoluminescence (PL), time-resolved (TR) PL, Raman spectroscopy, radioluminescence (RL), thermoluminescence (TL), and scintillation measurements, unveiled lattice strain induced by dual-organic cations in powder X-ray diffraction. Density functional theory analysis demonstrated a maximal 0.13 eV increase in the band gap with the addition of BZA cation addition. Notably, the largest Stokes shift of 0.06 eV was observed in (BZA)₂PbBr₄. The dual-organic cation crystals displayed >80% fast component scintillation decay time, which is advantageous for the scintillating process. Furthermore, we observed a dual-organic cations-induced enhancement of electron–hole transfer efficiency by up to 60%, with a contribution of >70% to the fast component of scintillation decay. The crystal with the lowest BZA concentration, (PEA_1.9BZA_0.1)PbBr₄, demonstrated the highest LYs of 14.9 ± 1.5 ph/keV at room temperature. Despite a 55–70% decrease in LY for BZA concentrations >5%, simultaneous reductions in scintillation decay time (12–32%) may work for time-of-flight positron emission tomography and photon-counting computed tomography. Our work underscores the crucial role of dual-organic cations in advancing our understanding of 2D-HOIP crystals for materials science and radiation detection applications.

中文翻译：

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双有机阳离子对二维杂化钙钛矿闪烁体结构和性能的影响


二维 (2D) 有机-无机杂化钙钛矿 (HOIP) 晶体有望作为宽能辐射检测的闪烁材料，其性能优于三维同类材料。在本研究中，我们利用苯乙基铵 (C BZA _x )PbBr ₄ （x 范围为 0.1 至 2）的单晶。 > H ₅ CH ₂ CH ₂ NH ₃ ⁺ ) 和苄基铵 (C < b9> H ₅ CH ₂ NH ₃ ⁺ ）阳离子。这些材料表现出良好的光学和闪烁特性，使其适用于高光产率 (LY) 和快速响应闪烁体。我们的研究采用各种技术，如 X 射线衍射 (XRD)、光致发光 (PL)、时间分辨 (TR) PL、拉曼光谱、放射发光 (RL)、热释光 (TL) 和闪烁测量，揭示了晶格应变诱导通过粉末 X 射线衍射中的双有机阳离子。密度泛函理论分析表明，随着 BZA 阳离子的添加​​，带隙最大增加了 0.13 eV。值得注意的是，在 (BZA) ₂ PbBr ₄ 中观察到最大斯托克斯位移为 0.06 eV。双有机阳离子晶体表现出>80%的快速组分闪烁衰减时间，这对于闪烁过程是有利的。此外，我们观察到双有机阳离子诱导的电子-空穴传输效率提高高达 60%，对闪烁衰变的快速分量的贡献>70%。 BZA 浓度最低的晶体 (PEA _1.9 BZA _0.1 )PbBr ₄ 在室温下表现出最高的 LY，为 14.9 ± 1.5 ph/keV。 尽管 BZA 浓度 >5% 时 LY 降低 55-70%，但闪烁衰减时间 (12-32%) 的同时减少可能适用于飞行时间正电子发射断层扫描和光子计数计算机断层扫描。我们的工作强调了双有机阳离子在增进我们对 2D-HOIP 晶体在材料科学和辐射检测应用中的理解方面的关键作用。