Self-aligned inkjet printing of resistors and low-pass resistor-capacitor filters on roll-to-roll imprinted plastics with resistances ranging from 10 to 10⁶ Ω

Resistors are essential and ubiquitous building blocks in electronic circuits. Fabrication of printed resistors in a manner compatible with roll-to-roll printing is important for realizing low-cost and high-throughput production of electronic devices. Here we present fully printed resistors fabricated via a novel self-aligned printing method, termed self-aligned capillarity-assisted lithography for electronics (SCALE). Flexible substrates with imprinted features such as reservoirs and capillary channels were prepared by roll-to-roll processing. Functional inks were then delivered sequentially into the reservoirs by inkjet printing and the ink flowed spontaneously into the adjoining channels driven by capillarity. Poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) was used as the resistive material, and silver was used for the electrodes. Using SCALE, we achieved fully inkjet-printed, self-aligned resistors with resistance values ranging over five orders of magnitude while keeping the overall dimensions of the devices constant. We then employed SCALE to build low-pass resistor-capacitor filters with cutoff frequency from 0.4 to 27 kHz and excellent operational stability. Overall, this work expands the potential of self-aligned inkjet printing for producing fully printed electronic circuits.