Role of tert-butyl in the linear and nonlinear optical property of push-pull chromophores

Through comparing the linear and nonlinear optical property of two pull-push chromophores, which are composed of difluoroboron beta-diketonate functionalized with carbazole and tert-butyl carbazole, the role of tert-butyl in chromosphere has been discussed in detail. The tert-butyl unit would lead to the absorption and fluorescence peak red shift and accelerate the fluorescence relaxation rate of chromophores. Moreover, the tert-butyl unit would affect obviously the two-photon optical property of chromophore according to the Z-scan test. The transient absorption (TA) data shows that these two pull-push chromopphores both own intramolecular charge transfer (ICT) characteristics and the tertbutyl unit accelerate the dynamic rate of ICT generation and relaxation process, which may be responsible for the variance of fluorescence property. (c) 017 Elsevier B.V. All rights reserved.