Performance and Stability of Flexible Low-Voltage Organic Transistors on Paper Substrates

Abstract

Paper has emerged as a potential substrate for biodegradable and sustainable electronics. In this work, high-performance flexible organic transistors on a paper substrate were demonstrated using simply an engineered bilayer gate dielectric consisting of polyvinyl alcohol (PVA) and polyacrylic acid (PAA), which was previously reported by us on flexible plastic substrates. The superstrong hydrogen bonding between PVA and PAA as confirmed through fourier-transform infrared (FTIR) spectroscopy makes it a promising bilayer for solution-processed gate dielectrics, yielding highly reliable flexible transistors. For a −5 V operation, the devices exhibited high performance with a field-effect mobility up to 0.5 cm2 V–1 s–1, a near-zero threshold voltage, a high Ion/Ioff ∼ 104, and high stability as observed through measurements for repeatability, bias stress, and cyclic stability for 500 cycles. High electromechanical stability with negligible variation in performance was achieved upon application of bending in various ways such as concave, convex, and twist bending. Resistive load inverters with these p-channel devices showed decent switching, confirming the suitability of these transistors in circuit applications. Though the performance of the devices was degraded upon heating above 50 °C, the devices exhibited very high environmental stability for more than 30 weeks in ambient conditions. In addition, a high degree of disintegration was observed in these paper devices due to the capability of biodegradability in soil with a biofertilizer.