Organic complementary circuits and resistive memory patterned by inkjet

The availability of n and p-channel solution-processed semiconductors enables the fabrication of complementary circuits, which have the advantages of lower power consumption and simpler design compared to unipolar circuits. At PARC, organic complementary circuits have been demonstrated by inkjet printing. Typical carrier mobilities for these printed TFTs are ~0.1 cm^2/Vs for both semiconductors with current on-to-off ratios >10^4, and the inverters showed a typical gain of 8 with VDD at 20V. With the charge trapping rates for n- and p-channel devices taken into account, we have designed decoder circuits to address passive matrix arrays. We will discuss how we address the challenges of device variations and stability. In additional to complementary circuits, non-volatile memory devices are also crucial to printed electronic applications. We have developed resistive memories to facilitate integration of memory with printed systems. Here metal/oxide/metal junctions were the memristive devices (named from memristors, short for memory resistors), and they were utilized to demonstrate a threshold detector, in which the printed memristive junctions were connected with a piezo voltage-pulse input and an electrophoretic display output. The memristive circuit would switch the color of display pixels depending on the number of input pulses sensed by the piezo. This demonstration used only passive elements and no battery and illustrated the potentials of using memristive elements in printed electronics.