Contact poling

Figure 1. (A) Time dependence of the second harmonic coefficient of a PPO-NPP film (1.4 NPP moieties per polymer repeat unit) contact-poled at 1.2 MV/cm. Decay data taken at 25°C. The data points are shown as filled triangles. The two curves describing the biexponential fit to equation 1 are shown separately, with the open triangles representing data points dominating the short-term decay. (B) Time dependence of the second harmonic coefficient of a corona-poled PPO-NPP film (1.4 NPP moieties per repeat unit). Decay data taken at 25°C. The data points are shown as filled triangles. The two curves describing the biexponential fit to equation 1 are shown separately, with the open triangles representing data points dominating the short-term decay.

In the contact poling a large poling field is created through electrodes with the polymer thin film placed in between (Fig. 21). The film is heated up to the glass... 

Fig. 3.7 Sketch of two configuration for contact poling. Left coplanar waveguide geometry (CPW), right sandwich configuration (parallel plate electrodes)...

Poly(l,4-phenylenevinylene) (PPV) and its derivatives have been the subject of many studies on their structures and electrical, optical, and electroluminescence properties [113-115]. It is expected that the materials with donor and acceptor groups attached on a PPV backbone can maintain the poled state unrelaxed once properly poled, because PPV has a highly rigid backbone owing to its poly conjugated structure. A series of such types of polymers have been reported by Jin et al. [116]. The synthesis of one of these polymers (poly[ 2-methoxy-5-(2-(4-nitrophenyl)ethenyl)-l,4-phenyl-enevinylene -co-(l,4-phenylenevinylene)]) is shown in Scheme 5. The dy.y, of 4.2 pm V was obtained in the contact poled polymers. The SHG signal remained constant over a period of more than 1 month at room temperature. 

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