Polymer light emitting electrodes PLEDs

Deeper insight into CNT functionalities when used as a dopant for polymer solar cells and polymer light-emitting diodes (PLEDs) was presented by Xu et al. [329]. While the PLED gained from rather low CNT doping levels of about 0.02%, the solar cell performance increased further up to 0.2 wt %. The improved EQE of the OLED was explained by a better charge carrier injection from the electrode, whereas for the solar cell exciton dissociation is facilitated by the nanotubes [329]. 

According to the similar method, a fiber-shaped polymer light-emitting diode (PLED) was developed on the PET fiber by adip-coatingmethod exceptfor the thermal-evaporation of the outermost Al semitransparent electrode. This PET-based fiber-shaped PLED showed a high luminance of over 1000 cd m which was high enough for application in wearable... 

To demonstrate a-Si H TFT technology, a monochromatic red-light-emitting display (0.5 x 0.5 in.2) using 100 dpi 4-a-Si H TFTs AM-PLEDs with 50 x 50 pixels was fabricated. Here, 100 dpi represents the display resolution since the display has 50 dots (monochromatic pixels) for each row and column line. In this display, the pixel PLED structure is the same as the one shown in the insert of Figure 9.11a. In this a-Si H TFT AM-PLED, the cathode electrodes for each pixel were connected, and the polymer layers were removed from the contact pads with solvent. 

The simplest light-emitting devices with conjugated polymers (PLEDs) are realized in such a manner that the polymer is arranged between two metal electrodes (see Figs. 30.7 and 30.8) [6,10]. The mechanism of the charge carrier injection into the polymer is discussed later in this section and in Section IV, whereas the... 

The process used for the photovoltaic device can be reversed to produce a light emitting diode (LED). When an electric field is applied to the two electrodes shown in Figure 1.7, electrons are injected into the conduction band of the polymer layer from the cathode (usually a low-work-function metal such as aluminum or calcium). At the ITO anode, electrons are removed from the valence band of the polymer to produce vacancies, or holes. The free electrons and holes move in opposite directions under the influence of the electric field and, when they combine, a photon of light is emitted. The color of the light emitted depends on the band gap between the valence and conduction bands in the polymer. Appropriate derivation of PPV polymers has produced PLEDs that emit the three colors red, blue and green. 

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