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We present a process for manufacturing printable thin-film transistors (TFTs) that is based on solution processing and direct inkjet printing of polymer semiconductors, dielectrics, and conductors, as well as inorganic nanoparticle conductors. We show that the high device yield, uniformity, and resolution required for thin-film electronic applications can be achieved by using a substrate that contains a surface energy pattern to control the flow and spreading of inkjet droplets. This technique overcomes many of the limitations of current inkjet printing technology related to its limited droplet placement accuracy. We demonstrate the potential of this printing-based TFT manufacturing process with the fabrication of 50 dpi active-matrix, polymer dispersed liquid-crystal and Gyricon Smartpaper electronic paper displays.

In thin metal films the phase change on reflection of incident light is dependent on the wavelength, the angle of incidence, the type of metal, and the metal thickness. These properties have been exploited to improve the performance of planar metal mirror microcavities. We model substantial alteration of peak emission wavelength and linewidth with mirror thickness. This allows the tuning of the cavity resonance wavelength by variation of metal mirror thickness. The dependence of the phase change on wavelength and angle of incidence can also be used to suppress the angular dependence of the cavity resonance wavelength. These effects are observed in silver-mirrored cavities containing the polymers poly(p-phenylene vinylene), (PPV), and a cyano-substituted derivative of PPV, MEH-CN-PPV.

We report an improved microcavity design which allows the suppression of the viewing angle dependence of the color emitted by a planar device. This is demonstrated for luminescent conjugated polymer based cavities, for which the wavelength change is reduced from ∼60 to 10 nm at an angle of 60°. We introduce the concept of cavity optical length dispersion and suggest structures for which the wavelength change with viewing angle is reduced to 5 nm at a viewing angle of 60° irrespective of the emissive material.

A scalable manufacturing process for fabricating active-matrix backplanes on low-cost flexible substrates, a key enabler for electronic-paper displays, is presented. This process is based on solution processing, ink-jet printing, and laser patterning. A multilayer architecture is employed to enable high aperture ratio and array performance. These backplanes were combined with E Ink electrophoretic media to create high-performance displays that have high contrast, are bistable, and can be flexed repeatedly to a radius of curvature of 5 mm