Fully roll-to-roll gravure printed 4-bit code generator based on p-type SWCNT thin-film transistors

Abstract

Current Si-based technologies have reached their intrinsic limits in meeting the demands of flexible electronics where free-form factors and low cost are critical for successful applications. For this reason, roll-to-roll (R2R) gravure printing has been considered a way to achieve the free-form factor and the low cost. However, the R2R gravure systems (servomechanism, electronic ink, printing process, and device design) could not integrate a number of thin-film transistors (TFTs) with small threshold voltage (V th) variations. Therefore, we designed a 4-bit code generator by combining one ring oscillator, six NAND gates, and one OR gate based on 37 p-type single-walled carbon nanotube (SWCNT) TFTs as a concept devices to test the R2R gravure system. First, ring oscillators with different physical dimensions were printed on a poly (ethylene terephthalate) roll using the R2R gravure. Then, we extracted important factors (channel length, channel width, and SWCNT network density) to optimize the V th variation and demonstrated a 4-bit code generator integrated with 37 p-type TFTs. This work will be further extended in the near future to develop R2R gravure printed near-field communication labels for smart packaging.

Rapid Uniformity Analysis of Fully Printed SWCNT-Based Thin Film Transistor Arrays via Roll-to-Roll Gravure Process

“…An R2R gravure printing system (i-PEN, Hwaseong-si, Korea) with two printing units ( Figure S1 in the Supplementary Materials ) was utilized to fabricate an SWCNT-TFT array on a PET substrate (250 mm wide, 100 µm thick, AH71D, SKC, Seoul, Korea). The overall R2R gravure printing conditions, including ink conditions (formulation), were identical to the conditions reported in our previous work [ 13 , 14 ]. The gate layer and dielectric layer were printed sequentially using Ag nanoparticle-based and BaTiO 3 -based inks.…”

“…After that, the SWCNT-based ink was printed on the dielectric/gate layers to form the active layer. The SWCNT-based ink formulation was identical to the ink reported in our previous work [ 14 ]. Lastly, the drain and source layers were overlay-printed on the SWCNT semiconducting layer using the same Ag nanoparticle-based ink.…”

Active Matrix Flexible Sensory Systems: Materials, Design, Fabrication, and Integration

“…[ 68 ] Furthermore, this process is capable of fabricating devices on soft, flexible, and nontraditional substrates in a roll‐to‐roll manner. [ 63 ] Due to these advantages, the solution processable ink‐based printing technologies, such as inkjet printing (Figure 5c), [ 145,146 ] transfer printing, [ 16 ] screen printing, [ 147 ] gravure printing, [ 63 ] and roll‐to‐roll printing, [ 32,148,149 ] have been employed for the fabrication of various active matrix flexible sensory systems.…”

“…[68] Furthermore, this process is capable of fabricating devices on soft, flexible, and nontraditional substrates in a roll-to-roll manner. [63] Due to these advantages, the solution processable ink-based printing technologies, such as inkjet printing (Figure 5c), [145,146] transfer printing, [16] screen printing, [147] gravure printing, [63] and roll-to-roll printing, [32,148,149] have been employed for the fabrication of various active matrix flexible sensory systems. Among the solution-processed ink-based printing technologies, the digital inkjet printing technique has caught great attention because it offers a versatile and low-cost methodology to integrate diverse functional materials on the same chip by designing the ink formulations, the substrate wettability, and the printing manners.…”

Effect of Radial Stress on the Nanoparticle-Based Electrolyte Layer in a Center-Wound Roll with Roll-to-Roll Systems

“…Roll-to-roll systems are suitable candidates for achieving high speed and mass production of flexible functional devices, such as flexible printed electronics, solar cells, fuel cells, bioelectric sensors, and pressure capacitive sensors [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. The slot-die coating process has the advantages of a large-area and pre-metered coating; therefore, it is used in the mass production of large-area functional layers [ 8 , 9 , 10 , 11 ].…”