Hydrogel‐Enabled Transfer‐Printing of Conducting Polymer Films for Soft Organic Bioelectronics

Abstract

The use of conducting polymers such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) for the development of soft organic bioelectronic devices, such as organic electrochemical transistors (OECTs), is rapidly increasing. However, directly manipulating conducting polymer thin films on soft substrates remains challenging, which hinders the development of conformable organic bioelectronic devices. A facile transfer-printing of conducting polymer thin films from conventional rigid substrates to flexible substrates offers an alternative solution. In this work, it is reported that PEDOT:PSS thin films on glass substrates, once mixed with surfactants, can be delaminated with hydrogels and thereafter be transferred to soft substrates without any further treatments. The proposed method allows easy, fast, and reliable transferring of patterned PEDOT:PSS thin films from glass substrates onto various soft substrates, facilitating their application in soft organic bioelectronics. By taking advantage of this method, skin-attachable tattoo-OECTs are demonstrated, relevant for conformable, imperceptible, and wearable organic biosensing.

Study of Partially Transient Organic Epidermal Sensors

“…A similar bonding mechanism was reported for a substrate-free graphene tattoo [30]. Studies showed that PEDOT:PSS could stably function on human-skin glucose monitoring [60] and electromyography [32], demonstrating the stable chemical and electronic properties of PEDOT:PSS on human skin. While there is a self-attached PEDOT:PSS tattoo sensor, water in excessive sweat might turn the PEDOT:PSS into hydrogel [61].…”

Regiorandom Polythiophenes for Fully Stretchable Electrochemical Transistors and Logic Circuits

“…Despite recent advances, achieving both high stretchability and a high on/off ratio in fully stretchable OECTs remains a significant challenge. The RRa‐P3DT OECTs developed in this study occupy the upper‐right region of the on/off ratio vs. stretchability plot, highlighting the superior performance of this device platform for future stretchable electronics (Figure 5d; Table S2) [22–34]. The µC* and transconductance values of the RRa‐P3DT OECTs in Table S2 are lower than those of state‐of‐the‐art PEDOT:PSS‐ or P(g2T‐T)‐based OECTs, but remain comparable to the typical ranges reported for regioregular polythiophene‐based OECTs ( µC* : 20 – 90 F cm − 1 V − 1 s − 1 ; normalized transconductance ( g m,norm ): 6 – 20 S/cm) [46, 55–57].…”

Intrinsically Stretchable Organic Electrochemical Transistors with Rigid‐Device‐Benchmarkable Performance

“…[ 43 , 44 , 45 ] The overall performance of the stretchable OECTs is summarized in Figure 4d and Table S1 , Supporting Information. [ 13 , 21 , 24 , 25 , 26 , 28 , 46 , 47 , 48 , 49 ] To conclude, the device showed record‐high on/off ratio (≈10 4 ), high mobility (≈1 cm 2 V −1 s −1 ), and intrinsically stretchability (>50%). This is the first time these merits can be harvested in one intrinsically stretchable OECT, encouraging its immediate use for various soft bioelectronics applications.…”