An integrated organic passive pixel sensor

We demonstrate an imaging passive pixel sensor circuit consisting of a bottom-gate, top-contact pentacene organic thin-film transistor (OTFT) integrated with a top-illuminated, inverted subphthalocyanine/C60 organic photodetector (OPD). The vacuum-deposited OTFT utilizes parylene as the gate insulator, achieving a drain current ON/OFF ratio of 105. The transistor hole mobility is 0.09 ± 0.02 cm2/V s. The inverted OPD has a dark current of 20 pA at a reverse bias of 1.5 V. By integrating the two components, a 12-bit dynamic range passive pixel sensor is achieved, with an OFF current of 31 ± 5 pA and a pixel readout time of 0.4 ± 0.05 ms, limited by the discharge time of the OTFT channel. The integrated pixel has potential for use in large-scale focal plane array imagers.

Figure optionsDownload as PowerPoint slideHighlights
► We demonstrate an integrated organic thin film transistor and photodetector.
► Applications to high sensitivity (detectivity >1011 Jones), high dynamic range (12-bit) imagers.
► Four hundred microsecond response suitable for video imaging.
► Off current of 30 pA.