花菁衍生物/上转换纳米复合材料的制备与发光性质

Preparation and luminescence properties of cyanine dye-sensitized upconversion nanocomposites

利用有机染料敏化上转换纳米材料可以拓展近红外光吸收,然而染料在纳米粒子表面易于聚集限制了上转换发光的提高。本文以花菁IR820为原料,在强碱作用下合成了含有四苯乙烯基团的2-(4-(1,2,2-三苯基乙烯基)苯氧基)环己烯-1-基)乙烯基)-3,3-二甲基-3H-苯并[f]吲哚-1-基)丁烷-1-磺酸盐(CyBTSO);利用自组装方法制备了IR820、CyBTSO敏化的上转换纳米复合材料,并对它们的结构和形貌等进行了表征。测试了染料在溶液、聚集态的光物理性能及染料敏化复合材料的上转换发光,系统研究了染料分子结构与上转换发光性能之间的关系。结果表明:四苯乙烯基团的引入不仅有利于提高CyBTSO的荧光量子产率和寿命,还能增强其稳定性,并抑制其在纳米粒子表面的聚集。与IR820相比,CyBTSO在纳米粒子表面的稳定性提高了1.7倍,负载量提高了3倍。在808 nm激发下,CyBTSO敏化纳米粒子的上转换发光强度比β-NaYF4:Yb20%,Er2%(980 nm)提高了69倍。本文为设计高效、稳定的上转换材料提供了理论借鉴。

Organic dye-sensitized upconversion nanomaterials can expand the absorption of near-infrared light,but dye-aggregation on the surface of nanoparticles limits the improvement of upconversion luminescence.In this paper,sodium 4-(2-((E)-2-((E)-3-((E)-2-(3,3-dimethyl-1-(4-sulfonatobutyl)-1,3-dihydro-2H-benzo[f]indol-2-ylidene)ethylidene)-2-(4-(1,2,2-triphenylvinyl)phenoxy)cyclohex-1-en-1-yl)vinyl)-3,3-dimethyl-3H-benzo[f]indol-1-ium-1-yl)butane-1-sulfonate(CyBTSO)containing tetrastyrene group was synthesized from cyanine IR820 in the presence of strong alkali.IR820 and CyBTSO sensitized upconversion nanocomposites were prepared by a self-assembly method,and their structures and morphologies were characterized.The photophysical properties of dyes in solution and condensed state,as well as the upconversion luminescence of dye-sensitized nanocomposites were investigated.The relationship between molecular structure and upconversion luminescence was systematically studied.It is found that the introduction of tetrastyrene group is not only beneficial to improve the fluorescence quantum yield and lifetime of CyBTSO,but also to enhance its stability and inhibit its aggregation on the nanoparticle surface.Compared with IR820,the stability and the loading amount of CyBTSO on the nanoparticle surface are increased by 1.7 and 3 times,respectively.As a result,a 69-fold enhancement of upconversion luminescence in CyBTSO-sensitized nanocompo-sites excited at 808 nm is achieved compared to that inβ-NaYF4:Yb20%,Er2%excited at 980 nm.This work provides a theoretical reference for the development of upconversion materials with high upconversion efficiency and stability.