Choudhary Mahendra B, Johnson Delna, Das Deep Kumar, Thiruvenkatam Vijay, Kundu Janardan, Hathwar Venkatesha R
School of Physical and Applied Sciences, Goa University, Taleigao Plateau, Goa, 403206, India.
Department of Chemistry, Indian Institute of Technology Gandhinagar, Palaj, Gujarat, 382355, India.
Sci Rep. 2025 Jul 1;15(1):20605. doi: 10.1038/s41598-025-93239-3.
The scheelite type sodium lanthanide double tungstates NaRE(WO) (RE = Sm, Ho and Pr) were synthesized by three different synthesis methods, namely solid-state reaction, hydrothermal method and solvothermal method using ethylene glycol. The synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy, UV-DRS and photoluminescence spectroscopy. The phase pure sample preparations with the Scheelite-like crystal structure in I4/a space group were established by XRD. Among the three synthesis methods, the broader XRD peaks were noticed for the solvothermal samples and resulting in crystallite sizes of ~ 11-28 nm. The SEM micrographs supported the XRD results and the agglomeration of particles with similar morphology was confirmed for all synthesis methods. The smallest particle size was obtained in the solvothermal method with average particle size distributions of ~ 100-140 nm. Indeed, the synthesis methods and particle size played a crucial role in the photoluminescence (PL) emission spectra. The PL emission intensity was very low for as-synthesized solvothermal samples where the particle size was considerably smaller compared to the other two methods. However, the calcination of solvothermal samples at different temperatures has improved their PL emission such that the emission intensity gradually increased with increasing the calcination temperature. Simultaneously, the SEM confirmed that the particle size remained the same till the calcination temperature of 600 °C. The microbial cell viability and cytotoxicity experiments were performed on the solvothermal samples using E. coli, S. aureus and HeLa cells, respectively. The biological studies demonstrated the biocompatibility of synthesized samples. The biocompatibility and smaller particle size in the solvothermal method could be useful in developing improved phosphors for cell imaging and theranostic applications.
采用三种不同的合成方法，即固态反应法、水热法和以乙二醇为溶剂的溶剂热法，合成了白钨矿型钠镧系双钨酸盐NaRE(WO)（RE = Sm、Ho和Pr）。通过X射线衍射（XRD）、扫描电子显微镜、紫外可见漫反射光谱（UV-DRS）和光致发光光谱对合成的样品进行了表征。通过XRD确定了在I4/a空间群中具有类白钨矿晶体结构的纯相样品制备方法。在这三种合成方法中，溶剂热法制备的样品XRD峰较宽，微晶尺寸约为11-28nm。扫描电子显微镜图像支持了XRD结果，并且证实了所有合成方法制备的颗粒都具有相似形态的团聚现象。溶剂热法得到的颗粒尺寸最小，平均粒径分布约为100-140nm。实际上，合成方法和颗粒尺寸在光致发光（PL）发射光谱中起着至关重要的作用。对于刚合成的溶剂热法样品，其PL发射强度非常低，与其他两种方法相比，其颗粒尺寸要小得多。然而，在不同温度下对溶剂热法样品进行煅烧提高了它们的PL发射，使得发射强度随着煅烧温度的升高而逐渐增加。同时，扫描电子显微镜证实，直到600℃的煅烧温度，颗粒尺寸都保持不变。分别使用大肠杆菌、金黄色葡萄球菌和HeLa细胞对溶剂热法样品进行了微生物细胞活力和细胞毒性实验。生物学研究证明了合成样品的生物相容性。溶剂热法中较小的颗粒尺寸和生物相容性对于开发用于细胞成像和治疗诊断应用的改进型荧光粉可能是有用的。
