Pawlik Natalia, Goryczka Tomasz, Zubko Maciej, Śmiarowska Joanna, Pisarski Wojciech A
University of Silesia, Institute of Chemistry, Szkolna 9 Street, 40-007 Katowice, Poland.
University of Silesia, Institute of Materials Engineering, 75. Pułku Piechoty 1A Street, 41-500 Chorzów, Poland.
Nanoscale. 2024 Feb 22;16(8):4249-4265. doi: 10.1039/d3nr04030e.
In this work, we report the results of our investigations on the structural and luminescence properties of SiO-LaF:Pr nano-glass-ceramics synthesized using the sol-gel method. Based on XRD, microscopic (TEM), and ATR-IR measurements, the crystallization of LaF nanocrystals favorably occupied by Pr ions and overall transformations within the silicate sol-gel hosts dependent on heat-treatment conditions of the as-prepared amorphous xerogels were characterized. The fabricated oxyfluoride nano-glass-ceramics revealed the emissions within the greenish-blue (P → H, P → H), reddish-orange (P → H, D → H, P → F), and NIR spectral scopes (D → F,G, G → H, F → H). Based on the luminescence spectra in the VIS range, the CIE chromaticity coordinates, correlated color temperatures (CCT), and color purities (CP) were calculated. The obtained results clearly indicate that the prepared Pr-doped sol-gel nano-glass-ceramics exhibit warm or neutral white light emissions with CCT values in the range from 2567 K to 3962 K. The lowest CP value was estimated at 12.8%, indicating that the fabricated samples are able to emit bright white light. Additionally, the NIR emissions cover E, S, C, and L bands, which are important for devices applicable in telecommunication technologies. For further characterization, the (P) and (D) decay times were estimated. It was established that the emissions from the P and the D excited states of Pr ions, as well as the participation of cross-relaxation (CR) processes, are dependent on the size of crystallized LaF phase, distribution of optically active Pr ions between amorphous and crystalline phase (determining the Pr-Pr inter-ionic distances), and relative content of OH groups in the prepared sol-gel hosts.
在本工作中，我们报告了使用溶胶-凝胶法合成的SiO-LaF:Pr纳米玻璃陶瓷的结构和发光性能的研究结果。基于X射线衍射（XRD）、显微镜（透射电子显微镜，TEM）和衰减全反射红外光谱（ATR-IR）测量，表征了由Pr离子占据的LaF纳米晶体的结晶情况以及取决于所制备的无定形干凝胶热处理条件的硅酸盐溶胶-凝胶主体内的整体转变。所制备的氧氟化物纳米玻璃陶瓷在绿蓝色（P→H，P→H）、红橙色（P→H，D→H，P→F）和近红外光谱范围（D→F，G，G→H，F→H）内显示出发射。基于可见光范围内的发光光谱，计算了CIE色度坐标、相关色温（CCT）和色纯度（CP）。所得结果清楚地表明，所制备的Pr掺杂溶胶-凝胶纳米玻璃陶瓷表现出暖白色或中性白色发光，CCT值在2567 K至3962 K范围内。最低CP值估计为12.8%，表明所制备的样品能够发射明亮的白光。此外，近红外发射覆盖E、S、C和L波段，这对于适用于电信技术的器件很重要。为了进一步表征，估计了（P）和（D）衰减时间。已确定Pr离子的P和D激发态的发射以及交叉弛豫（CR）过程的参与取决于结晶LaF相的尺寸、光学活性Pr离子在非晶相和结晶相之间的分布（决定Pr-Pr离子间距离）以及所制备的溶胶-凝胶主体中OH基团的相对含量。
