Novel Guest-Host NLO Polyimide Based on Two-Dimensional Carbazole Chromophores
- PDF / 333,237 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 5 Downloads / 146 Views
Novel Guest-Host NLO Polyimide Based on Two-Dimensional Carbazole Chromophores Wen-Jang Kuo1, Ging-Ho Hsiue*1, and Ru-Jong Jeng2 1. Dept of Chemical Engineering, National Tsing Hua University, Hsinchu, Taiwan, 300, ROC. 2. Dept of Chemical Engineering, National Chung Hsing University, Taichung, Taiwan, 402, ROC. ABSTRACT Taking advantage of the multifunctional characteristics of carbazole along with rational molecular design, several two-dimensional carbazole chromophores were acquired. Doping the chromophores into poly(ether imide), a series of NLO-active guest-host polymers were obtained. The compatibility between chromophores and poly(ether imide) was investigated by SEM and extraction experiment. After poling, these NLO poly(ether imide)s with large second-order nonlinearities were achieved. Correlation between structure and nonlinear optical characteristics, and the chromophore size effect on the thermal and temporal stability have been probed. Large rotational cone volumes make the two-dimensional chromophores possessing . excellent orientational stability at 60 INTRODUCTION Organic second-order nonlinear optical (NLO) materials have attracted interest because of their potential applications in optoelectronic technology [1, 2]. Most of attempted chromophores are designed as one-dimensional “push–pull” compounds. These chromophores exhibit large first hypersusceptibility, β. However, the one-dimensional compounds provide less phase-matching behavior owing to their small off-diagonal component [3, 4]. Two-dimensional (2-D) chromophores have been observed, possessing better phase-matching than one-dimensional chromophores because of their larger off-diagonal components [5]. In this work, the macroscopic NLO properties of the 2-D chromophores were further investigated through guest–host systems. C6H13 C6H13 C6H13
N
N
N O
O O2N
2DNO2
NO2
S
S O2 N
2DPhNO2
NO2
Et
O
Cz2PhSO2 O
Et
(a)
O
F3C
CF3 C
O
N
N
O
O (b)
O
O n
6FPEI
Figure 1 shows (a) the 2-D chromophores and (b) the organosoluble poly(ether imide), 6FPEI. The carbazole derivatives were chosen as the 2-D NLO chromophores because of their multifunctional properties, such as second-order NLO and photorefractive properties [6, 7]. The C5.26.1
organosoluble poly(ether imide), 6FPEI, based on bis(aminophenoxy)biphenyl was served as the polymeric matrices for the guest-host NLO systems. A systematic investigation of variation of the chromophoric structures on NLO properties has been pursued. The correlation between structure and nonlinear optical characteristics was investigated by thermal dynamic and temporal relaxation behaviors, and dielectric analysis. The compatibility between chromophores and polymer matrix was also studied by SEM and extraction experiment. EXPERIMENTAL DETAILS The 2-D chromophores were obtained according to literatures [8]. By dissolving 1-gram of polyetherimide and 0.3 mmol of chromophores into spectroscopic grade N-methyl pyrrolidone (NMP), a series of guest-host NLO systems were acquired. High-quality polymer film
Data Loading...
