基于Trger's Base的强荧光化合物纳米晶的尺寸效应(英文)

Size-dependent Properties of Highly Fluorescent Trger's Base Nanocrystals

利用再沉淀法制备了极性不同的两种基于Tr ger's碱的化合物:4,13-二(4-联苯)-6,6,11,11-四丁基-9H,18H-8,17-甲基二芴(2,3-b:2',3'-f)(1,5)二氮芳辛(TBFB-BP)和4,13-二(4-N,N-二苯基苯胺)-6,6,11,11-四丁基-9H,18H-8,17-甲基二芴(2,3-b:2',3'-f)(1,5)二氮芳(TBFB-TPA)的有机纳米晶。由于Λ-扭折构型的空间位阻作用,这两种化合物在溶液、纳米粒子悬浊液和固态粉末下均显示出强蓝色荧光。随着化合物纳米粒径的增加,TBFB-BP纳米粒子悬浊液的吸收光谱红移,发射光谱增强,这可能是由于随着纳米粒径的增加,纳米粒子的晶格刚性增强,使其振动驰豫降低。但是对于极性更强的TBFB-TPA来说,由于溶剂效应,其发射光谱随着粒径的增大逐渐蓝移。此外还讨论了分子极性对尺寸效应的影响。

Nanocrystals of two Trger＇s base analogues：4,13-Di（biphenyl-4-yl）-6,6,11,11-tetrabutyl-9H,18H-8,17-methanodifluoreno（2,3-b：2＇,3＇-f）（1,5）diazocine （abbreviated as TBFB-BP） and 4,13-Di（4-N,N-diphenylaniline）-6,6,11,11-tetrabutyl-9H,18H-8,17-methanodifluoreno（2,3-b：2＇,3＇-f）（1,5）diazocine （abbreviated as TBFB-TPA）,with different polarity were prepared by a simple reprecipitation method.Strong blue fluorescence was observed in solution as well as in colloidal and solid states due to the special Λ-shaped configuration.A strong size dependence of continuous bathochromic absorption and significant enhanced emission were observed with the increase of the TBFB-BP particle size,which may be attributed to the enhanced rigidification of the crystal lattice and the associated decrease of vibrational relaxation of this compound.However,for TBFB-TPA that has larger polarity,the emission spectra exhibited obvious hypsochromic shift due to the effect of solvating interaction.The effect of molecular polarity on the size-dependent optical properties was discussed.