High-Frequency Rectifiers Based on Organic Thin-Film Transistors on Flexible Substrates

摘要

Rectifier circuits featuring low threshold voltages and high cutoff frequencies based on p-channel organic thin-film transistors (TFTs) have been designed, fabricated and characterized. The TFTs and circuits were fabricated by shadow-mask lithography on flexible plastic substrates using the vacuum-deposited small-molecule organic semiconductor dinaphtho[2,3-b:2',3'-f]thieno[3,2-b] thiophene (DNTT). The TFTs have a gate dielectric with a thickness of 5.3 nm and a channel length of 10 mu m. The study considers the frequency characteristics of diode-connected transistors (transdiodes) and adopts circuit techniques from silicon CMOS technology, namely single-stage and multistage dynamic-threshold-compensated differential rectifiers. The characterization of the rectifier circuits indicates cutoff frequencies up to 4.75 MHz at a peak-to-peak input voltage of 3 V for transdiodes, up to 32 MHz at a peak-to-peak input voltage of 1.5 V for single-stage differential rectifiers and up to 7.5 MHz at a peak-to-peak input voltage of 1.5 V for two-stage rectifiers. The efficiency is 25% for a load of 10 M Omega and below 1% for a load of 1 M Omega.