Blue full color displays

Electron-Deficient Polymers - Luminescent Transport Layers 16 Other Electron-Deficient PPV Derivatives 19 Electron-Deficient Aromatic Systems 19 Full Color Displays - The Search for Blue Emitters 21 Isolated Chromophores - Towards Blue Emission 21 Comb Polymers with Chromophores on the Side-Chain 22 Chiral PPV - Polarized Emission 23 Poly(thienylene vinylene)s —... 

Full Color Displays - The Search for Blue Emitters... 

Various ways of making full-color displays have been proposed. These are summarized in Figure 7.14. Perhaps the most obvious method is simply to fabricate red, green, and blue subpixels side by side on the same substrate (Figure 7.14a). Many companies have adopted this approach, e.g., Pioneer demonstrated a full-color QVGA (320 x 240 pixels) display at the Japan Electronics Show in 1998. Figure 7.15 is an example of a full-color display patterned using a side-by-side approach. 

Since blue, green and red LEDs are now available, white light can be obtained by mixing colors. We have already discussed stacked LEDs which give full color display or... 

Meerholz and coworkers incorporated the HTM (triphenyldiamine derivative) into the backbone of SPF to elevate the device efficiency through promoting hole injection/transport properties [24]. The cross-linkable oxetane-functionalized SPF derivatives 10-12 were also synthesized to realize full color display via spin-coating processes. The resulting EL devices (ITO/PEDOT PSS/10, 11, or 12/Ca/Ag) showed maximum efficiencies of 2.9, 7.0, and 1.0 cd A-1 for blue, green, and red emissions, respectively. 

For monochrome displays, a uniform film of the semiconducting polymer (as sketched in Fig. 4.16) can be spin-cast from solution. For full-color displays, both active matrix and passively addressed, individual red, green and blue pixels must be patterned and individually addressed. 

The colored liquids in Fig. 4.17 are examples of different semiconducting polymers in solution. These colored solutions can be thought of as functional inks and applied to substrates using the methods of modern printing technology. Inkjet printing appears to be an ideal way to deposit the red, green and blue pixels of a full-color display. Fig. 4.18 illustrates this remarkable opportunity. 

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