Chakraborty Ananya, Aman Shireen, Mishra Shubhra, Dubey Neha, Saji Janita, Kshatri D S, Dubey Vikas
Department of Physics, North-Eastern Hill University, Shillong, Meghalaya, India.
Department of Physics, Government Naveen College Gudhiyari, Raipur, India.
Luminescence. 2025 Sep;40(9):e70316. doi: 10.1002/bio.70316.
The advancement of non-invasive diagnostic tools has propelled the development of luminescent nanomaterials with enhanced imaging capabilities. In this study, Eu/Nd codoped CaSiO phosphors were synthesized via a conventional solid-state reaction route under a reducing environment to explore their potential for bioimaging applications. Calcium silicate, known for its intrinsic biocompatibility, served as the host matrix, whereas Eu acted as the primary luminescent centre and Nd was used as the near-infrared (NIR) sensitizer to support deep-tissue excitation. Structural analysis via X-ray diffraction (XRD) verified the formation of a triclinic crystal structure and the average crystallite size was validated through both Scherrer equation and Williamson-Hall analyses. Field emission gun scanning electron microscopy (FEG-SEM) images revealed flower-like microstructures with embedded fine white particles. Energy-dispersive X-ray spectroscopy (EDX) detected the existence of expected chemical components of the phosphor, whereas Fourier-transform infrared (FTIR) spectra provided evidence of successful dopant incorporation through characteristic vibrations corresponding to Ca-O, Si-O-Si, Eu-O and Nd-O bonds. Photoluminescence studies showed an excitation spectrum with distinct and intense absorption bands within the range of 700-1000 nm, attributed to the 4f-4f transitions of Nd ions, and upon excitation at approximately 800 nm, the phosphor exhibited dual emission bands around 410 and 440 nm with optimal intensity corresponding to the characteristic 4f5d → 4f transitions of Eu. The afterglow decay analysis showed persistent luminescence exceeding 15 min, and CIE chromaticity analysis confirmed that the emission lies within the blue spectral range (x = 0.155, y = 0.059), indicating high potential for background-free bioimaging with high chromatic accuracy. These findings suggest that Eu/Nd doped CaSiO can be a promising luminescent material for advanced biomedical imaging applications.
非侵入性诊断工具的进步推动了具有增强成像能力的发光纳米材料的发展。在本研究中，通过常规固态反应路线在还原环境下合成了Eu/Nd共掺杂的CaSiO磷光体，以探索其在生物成像应用中的潜力。硅酸钙因其固有的生物相容性而作为主体基质，而Eu作为主要发光中心，Nd用作近红外（NIR）敏化剂以支持深部组织激发。通过X射线衍射（XRD）进行的结构分析证实了三斜晶体结构的形成，并且通过谢乐方程和威廉姆森-霍尔分析验证了平均微晶尺寸。场发射枪扫描电子显微镜（FEG-SEM）图像显示出具有嵌入细白色颗粒的花状微观结构。能量色散X射线光谱（EDX）检测到了磷光体预期化学成分的存在，而傅里叶变换红外（FTIR）光谱通过对应于Ca-O、Si-O-Si、Eu-O和Nd-O键的特征振动提供了成功掺杂的证据。光致发光研究显示在700-1000 nm范围内有明显且强烈的吸收带的激发光谱，这归因于Nd离子的4f-4f跃迁，并且在约800 nm激发时，磷光体在410和440 nm左右呈现双发射带，其最佳强度对应于Eu的特征4f5d→4f跃迁。余辉衰减分析表明持续发光超过15分钟，并且CIE色度分析证实发射位于蓝色光谱范围内（x = 0.155，y = 0.059），表明具有高色度精度的无背景生物成像具有很高的潜力。这些发现表明Eu/Nd掺杂的CaSiO可以成为用于先进生物医学成像应用的有前途的发光材料。
