The influence of pentafluorophenyl groups on the nonlinear optical (NLO) performance of high generation dendrons and dendrimers
With the aim to make the influence of pentafluorophenyl groups in the periphery of high generation dendrons and dendrimers on their NLO performance clearly, some NLO dendrons and dendrimers with different chromophore moieties or different end-capped groups were carefully designed and investigated in detail. The results demonstrated that some strong Ar-ArF interactions between the pentafluorophenyl groups in the periphery and the normal phenyl rings of the donors, could influence the topological structures of dendrons or dendrimers, and then affect their NLO performance. Furthermore, the optical transparency and the stability of the dendrons and dendrimers with pentafluorophenyl groups as end-capped moieties were all improved, in comparison with normal dendrons and dendrimers containing phenyl ones as the end-capped groups.
Structural Control of the Side-Chain Chromophores To Achieve Highly Efficient Nonlinear Optical Polyurethanes
Two series of polyurethanes (P1−P10) containing NLO chromophores as side chains were prepared, in which the size of isolation groups was changed from small atoms to much larger groups such as carbazolyl groups. The polymers were well characterized. The tested NLO properties of the polymers demonstrate that the NLO values and the poling efficiency of the polymers are not always improved with increasing of the size of isolation spacer, and for a given chromophore moiety, there is a suitable isolation group present to boost its microscopic β value to possibly higher macroscopic NLO property efficiently.
Synthesis and nonlinear optical properties of branched pyrroline chromophores
New tricyanopyrroline (TCP) chromophores with rigid–flexible dendron were prepared for second-order nonlinear optical (NLO) application. The chromophores were fully characterized using ultraviolet-visible spectroscopy, nuclear magnetic resonance spectroscopy and mass spectrometry. Thermal gravimetric analysis (TGA) revealed that the chromophores had excellent thermal stability. Large λmax and high solvate chromic effects revealed that the chromophores had large second-order optical nonlinearity. The electro-optic coefficients (r33) were measured in the chromophores-doped poly(bisphenol A carbonate) films at the fundamental wavelength of 1310 nm, and the highest γ33 achieved was 217 pmV−1. Copyright © 2010 John Wiley & Sons, Ltd.