Flexible, polymer-based light sensor arrays on active-matrix backplanes fabricated by digital inkjet printing
As macro-electronics applications scale towards larger areas, array fabrication will become increasingly complex with conventional methods of device processing, such that photolithography and vacuum deposition will reach a practical limit. Low-temperature integration of inorganic and polymeric materials onto flexible platforms would enable low-cost, large-area image sensors by reducing materials and fabrication costs. We have developed prototypes of flexible light sensor arrays fabricated using polymeric sensor materials on polyethylene naphthalate substrates. The photo-sensitive materials were comprised of layered organic semiconductors, in which a transparent, hole-transporting layer of tetraphenyldiamine is spin-casted on top of a low bandgap polymer that dictates the spectral response of the sensor. The sensor layer has shown quantum efficiency of ~1% at 488 nm and a dark current of 1.1 pA/mm2. This layer is integrated onto a flexible a-Si:H active matrix backplane fabricated using digital inkjet printing to create a 180x180 pixel array with 75 dpi resolution. Sensor properties such as sensitivity, spectral response, and spatial resolution are determined and compared to those of conventional amorphous silicon photodiodes.
Ng, T. ; Wong, W. S. ; Lujan, R. A. ; Apte, R. B. ; Chabinyc, M. ; Limb, S. ; Street, R. A. Flexible, polymer-based light sensor arrays on active-matrix backplanes fabricated by digital inkjet printing. Materials Research Society Spring Meeting; 2007 April 9-13; San Francisco; CA; USA.