Xu Liting, Li Yi, Liu Wei, Yang Yonggang
State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Jiangsu Engineering Laboratory of Novel Functional Polymeric Materials, Department of Polymer Science and Engineering, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, P. R. China.
Mater Horiz. 2024 Dec 9;11(24):6455-6462. doi: 10.1039/d4mh00966e.
Upconversion circularly polarized luminescence (UC-CPL) exhibits promising potential for application for anti-counterfeiting and displays. Upconversion nanoparticles (UCNPs), NaYF:Yb,Tm, with uniform morphology and high crystallinity, were prepared a simple solvothermal method. These UCNPs were embedded into cholesteric liquid crystal polymer network (CLCN) films. The UC-CPL performance of these films was investigated using left- and right-handed circular polarizers. After calibration, the |callum| values (up to 0.33) were obtained for the free-standing CLCN-UCNPs films, while a |callum| value of 0.43 was achieved for the CLCN-UCNPs-coated PET film. Moreover, a combined system comprising a PMMA-UCNPs layer and a CLCN layer yielded an ultra-large |callum| value of up to 1.73. Flexible and colourful patterned CLCN films were fabricated using photomasks, offering potential applications in anti-counterfeiting. This study not only successfully prepared UC-CPL-active materials based on CLCNs and UCNPs, but also demonstrated the chiral filtering effect of CLCN films in upconversion luminescent materials.
上转换圆偏振发光（UC-CPL）在防伪和显示应用方面展现出了广阔的潜力。采用简单的溶剂热法制备了具有均匀形态和高结晶度的上转换纳米粒子（UCNPs）NaYF:Yb,Tm。将这些UCNPs嵌入胆甾相液晶聚合物网络（CLCN）薄膜中。使用左旋和右旋圆偏振器研究了这些薄膜的UC-CPL性能。经过校准，独立的CLCN-UCNPs薄膜获得了高达0.33的|callum|值，而CLCN-UCNPs涂层的PET薄膜的|callum|值达到了0.43。此外，由PMMA-UCNPs层和CLCN层组成的复合系统产生了高达1.73的超大|callum|值。使用光掩模制备了柔性且色彩丰富的图案化CLCN薄膜，在防伪方面具有潜在应用。本研究不仅成功制备了基于CLCN和UCNPs的UC-CPL活性材料，还证明了CLCN薄膜在上转换发光材料中的手性滤波效应。
