Szyszka Katarzyna, Targońska Sara, Lewińska Agnieszka, Watras Adam, Wiglusz Rafal J
Institute of Low Temperature and Structure Research, PAS, Okolna 2, 50-422 Wroclaw, Poland.
Faculty of Chemistry, University of Wroclaw, Joliot-Curie 14, 50-383 Wroclaw, Poland.
Nanomaterials (Basel). 2021 Feb 11;11(2):464. doi: 10.3390/nano11020464.
The hydroxyapatite nanopowders of the Eu-doped, Cu-doped, and Eu/Cu-co-doped Ca(PO)(OH) were prepared by a microwave-assisted hydrothermal method. The structural and morphological properties of the products were investigated by X-ray powder diffraction (XRD), transmission electron microscopy techniques (TEM), and infrared spectroscopy (FT-IR). The average crystal size and the unit cell parameters were calculated by a Rietveld refinement tool. The absorption, emission excitation, emission, and luminescence decay time were recorded and studied in detail. The D → F transition is the most intense transition. The Eu ions occupied two independent crystallographic sites in these materials exhibited in emission spectra: one Ca(1) site with C symmetry and one Ca(2) sites with C symmetry. The Eu emission is strongly quenched by Cu ions, and the luminescence decay time is much shorter in the case of Eu/Cu co-doped materials than in Eu-doped materials. The luminescence quenching mechanism as well as the schematic energy level diagram showing the Eu emission quenching mechanism using Cu ions are proposed. The electron paramagnetic resonance (EPR) technique revealed the existence of at least two different coordination environments for copper(II) ion.
采用微波辅助水热法制备了铕掺杂、铜掺杂和铕/铜共掺杂的Ca(PO)(OH)羟基磷灰石纳米粉末。通过X射线粉末衍射（XRD）、透射电子显微镜技术（TEM）和红外光谱（FT-IR）对产物的结构和形貌特性进行了研究。利用Rietveld精修工具计算了平均晶体尺寸和晶胞参数。详细记录并研究了吸收、发射激发、发射和发光衰减时间。D→F跃迁是最强的跃迁。在发射光谱中，铕离子占据了这些材料中的两个独立晶体学位置：一个具有C对称性的Ca(1)位置和一个具有C对称性的Ca(2)位置。铜离子强烈猝灭铕的发射，并且在铕/铜共掺杂材料中，发光衰减时间比铕掺杂材料中的短得多。提出了发光猝灭机制以及使用铜离子显示铕发射猝灭机制的示意能级图。电子顺磁共振（EPR）技术揭示了铜（II）离子至少存在两种不同的配位环境。
