Fully Screen‐Printed Stretchable Organic Electrochemical Transistors

Abstract

Stretchable organic electrochemical transistors (OECTs) are promising for wearable applications within biosensing, bio‐signal recording, and addressing circuitry. Efficient large‐scale fabrication of OECTs can be performed with printing methods but to date there are no reports on high‐performance fully printed stretchable OECTs. Herein, this challenge is addressed by developing fully screen‐printed stretchable OECTs based on an architecture that minimizes electrochemical side reactions and improves long‐term stability. Fabrication of the OECTs is enabled by in‐house development of three stretchable functional screen‐printing inks and related printing processes. The stretchable OECTs show good characteristics in terms of transfer curves, output characteristics, and transient response up to 100% static strain and 500 strain cycles at 25% and 50% strain. The strain insensitivity of the OECTs can be further improved by strain conditioning, resulting in stable performance up to 50% strain. Finally, an electrochromic smart pixel is demonstrated by connecting a stretchable OECT to a stretchable electrochromic display. It is believed that the development of screen‐printed stretchable electrochemical devices, and OECTs in particular, will pave the way for their use in wearable applications and commercial products.

Breathable and Stretchable Organic Electrochemical Transistors with Laminated Porous Structures for Glucose Sensing

“…The smaller effect of W-direction stretching can be explained by both that slight cracks are produced along the L-direction and that there is an increase in the W/L ratio. Conversely, L-direction stretching creates cracks perpendicular to the direction of charge transfer and a decreased W/L ratio [ 30 , 31 ]. As expected, g m, p along the L-direction and W-direction in the stretched state follows a similar trend to I on (g m, p along the W-direction changes from 1.860 mS in the pristine state to 0.825 mS at 30% strain and g m, p along the L-direction changes from 1.710 mS in the pristine state to 0.512 mS at 30% strain).…”

A Guide to Printed Stretchable Conductors

“…101,107 Advantages of screen printing relative to other methods discussed here include high resolution (∼100 μm is typical, but down to 5 μm is possible using special stencils), high throughput, low cost, and low material wastage. 97,108,109 Screen printing also offers flexibility to print conductive patterns and soft substrates. For example, polyimide (PI)-polyethylene glycol (PEG) composite as a soft substrate and Ag/AgCl-based conductive inks (minimum resolution: 150 μm) were sequentially screen printed using water as a solvent, as shown in Figure 4c.…”

Recent advances in the construction and application of stretchable PEDOT smart electronic membranes

“…Deposition methods include spin coating, spray coating, rod coating, 175 screen printing, 176 and chemical vapor deposition (CVD). 177 Spin coating can spin the solution or suspension on a substrate to a uniform thickness, 178 and has the advantages of simple preparation and low cost, but it is only suitable for flat substrates.…”