Wei Guodan, Lu Mengfan, Feng Kai, Ma Sijia, Jiang Yuqian, Jin Zhaoxia
Key Laboratory of Advanced Light Conversion Materials and Biophotonics, Department of Chemistry, Renmin University of China, 100872 Beijing, People's Republic of China.
Beijing National Laboratory for Molecular Science (BNLMS), Key Laboratory of Colloid, Interface and Chemical Thermodynamics, Institute of Chemistry, Chinese Academy of Sciences, ZhongGuanCun North First Street 2, 100190 Beijing, People's Republic of China.
ACS Omega. 2023 Jun 12;8(25):23191-23201. doi: 10.1021/acsomega.3c02969. eCollection 2023 Jun 27.
The chiral nematic nanostructure formed from cellulose nanocrystal (CNC) self-assembly has shown great potential as a matrix for generating circularly polarized luminescent (CPL) light with a high dissymmetry factor. Exploring the relationship between the device composition and structure and the light dissymmetry factor is crucial to a common strategy for a strongly dissymmetric CPL light. In this study, we have compared the single-layered and double-layered CNC-based CPL devices with different luminophores, such as rhodamine 6G (R6G), methylene blue (MB), crystal violet (CV), and silicon quantum dots (Si QDs). We demonstrated that forming a double-layered structure of CNCs nanocomposites is a simple but effective pathway for enhancing the CPL dissymmetry factor for CNC-based CPL materials containing different luminophores. The || values of double-layered CNC devices (dye@CNC5||CNC5) versus that of single-layered devices (dye@CNC5) are 3.25 times for Si QDs, 3.7 times for R6G, 3.1 times for MB, and 2.78 times for CV series. The different enhancement degrees of these CNC layers with a similar thickness may be due to the different pitch numbers in the chiral nematic liquid crystal layers whose photonic band gap (PBG) has been modified to match the emission wavelengths of dyes. Furthermore, the assembled CNC nanostructure has great tolerance to the addition of nanoparticles. Gold nanorods coated with the SiO layer (Au NR@SiO) were added for enhancing the dissymmetry factor of MB in CNC composites (named MAS devices). When the strong longitudinal plasmonic band of the Au NR@SiO matched the emission wavelength of MB and the PBG of assembled CNC structures simultaneously, the increase in the factor and quantum yield of MAS composites was obtained. The good compatibility of the assembled CNC nanostructures makes it a universal platform for developing strong CPL light sources with a high dissymmetry factor.
由纤维素纳米晶体（CNC）自组装形成的手性向列型纳米结构，作为一种用于产生具有高不对称因子的圆偏振发光（CPL）光的基质，已显示出巨大潜力。探索器件组成与结构和光不对称因子之间的关系，对于实现强不对称CPL光的通用策略至关重要。在本研究中，我们比较了基于单层和双层CNC的CPL器件，这些器件含有不同的发光体，如罗丹明6G（R6G）、亚甲基蓝（MB）、结晶紫（CV）和硅量子点（Si QDs）。我们证明，对于包含不同发光体的基于CNC的CPL材料，形成双层CNC纳米复合材料结构是提高CPL不对称因子的一种简单而有效的途径。双层CNC器件（dye@CNC5||CNC5）与单层器件（dye@CNC5）相比，Si QDs的||值为3.25倍，R6G为3.7倍，MB为3.1倍，CV系列为2.78倍。这些厚度相似的CNC层不同的增强程度，可能是由于手性向列型液晶层中不同的螺距数，其光子带隙（PBG）已被修改以匹配染料的发射波长。此外，组装的CNC纳米结构对添加纳米颗粒具有很大的耐受性。添加了涂有SiO层的金纳米棒（Au NR@SiO）以提高CNC复合材料中MB的不对称因子（命名为MAS器件）。当Au NR@SiO的强纵向等离子体带与MB的发射波长和组装的CNC结构的PBG同时匹配时，MAS复合材料的 因子和量子产率得到提高。组装的CNC纳米结构的良好兼容性，使其成为开发具有高不对称因子的强CPL光源的通用平台。
