Naresh Varnakavi, Cha Pil-Ryung, Lee Nohyun
School of Advanced Material Engineering, Kookmin University, Seoul 02707, Republic of Korea.
ACS Appl Mater Interfaces. 2024 Apr 17;16(15):19068-19080. doi: 10.1021/acsami.3c17301. Epub 2024 Apr 8.
Rare-earth-based double perovskite (DP) X-ray scintillators have gained significant importance with low detection limits in medical imaging and radiation detection owing to their high light yield (LY) and remarkable spatial resolution. Herein, we report the synthesis of 3D double perovskite (DP) crystals, namely, CsNaGdCl and Tb-CsNaGdCl using hydrothermal reaction. CsNaGdCl DP single crystals exhibited a blue self-trapped exciton (STE) emission at 470 nm under ultraviolet (265 nm) excitation with a photoluminescence quantum yield (PLQY) of 8.4%. Introducing Tb ions into CsNaGdCl has resulted in quenching of STE emission and enhancing green emission at 549 nm attributed to the D → F transition of Tb, suggesting efficient energy transfer (ET) from STE to Tb. This ET process is evidenced by the appearance of Tb bands in the excitation spectra of the host, the shortening of the STE lifetimes in the presence of Tb ions, and the enhancement of PLQY (72.6%). Furthermore, CsNaGdCl:5%Tb films of various thicknesses (0.1-0.6 mm) were synthesized and their X-ray scintillating performance has been examined. The CsNaGdCl:5%Tb film with 0.4 mm thickness has exhibited an excellent linear response to the X-ray dose rate with a low detection limit of 41.32 nGy s, an LY of 39,100 photons MeV, and excellent radiation stability. Benefiting from the strong X-ray excited luminescence (XEL) of CsNaGdCl:5%Tb, we developed a CsNaGdCl:5%Tb X-ray scintillator screen with a least thickness (0.1 mm), exhibiting remarkable imaging ability with a spatial resolution of 10.75 lp mm. These results suggest that CsNaGdCl:Tb can be a potential candidate for low-dose and X-ray imaging applications.
基于稀土的双钙钛矿（DP）X射线闪烁体因其高光产额（LY）和出色的空间分辨率，在医学成像和辐射检测中具有低检测限，已变得极为重要。在此，我们报告了使用水热反应合成3D双钙钛矿（DP）晶体，即CsNaGdCl和Tb-CsNaGdCl。CsNaGdCl DP单晶在紫外光（265 nm）激发下于470 nm处呈现蓝色自陷激子（STE）发射，光致发光量子产率（PLQY）为8.4%。将Tb离子引入CsNaGdCl导致STE发射猝灭，并增强了549 nm处归因于Tb的D→F跃迁的绿色发射，表明从STE到Tb的有效能量转移（ET）。这种ET过程通过主体激发光谱中Tb能带的出现、存在Tb离子时STE寿命的缩短以及PLQY的增强（72.6%）得到证明。此外，合成了不同厚度（0.1 - 0.6 mm）的CsNaGdCl:5%Tb薄膜，并研究了它们的X射线闪烁性能。厚度为0.4 mm的CsNaGdCl:5%Tb薄膜对X射线剂量率表现出优异的线性响应，检测限低至41.32 nGy s，LY为39,100光子/MeV，且具有出色的辐射稳定性。受益于CsNaGdCl:5%Tb的强X射线激发发光（XEL），我们开发了一种厚度最小（0.1 mm）的CsNaGdCl:5%Tb X射线闪烁体屏，其空间分辨率为10.75 lp/mm，具有出色的成像能力。这些结果表明CsNaGdCl:Tb可能是低剂量和X射线成像应用的潜在候选材料。
