Stretchable semiconducting polymer aerogel transistors for high-performance biosensors and artificial synapses

Stretchable organic electrochemical transistors (OECTs) are attractive for high-performance flexible electronics. Poly(3-hexylthiophene) (P3HT) and poly[2,5-(2-octyldodecyl)-3,6-diketopyrrolopyrrole-alt-5,5-(2,5-di(thien-2-yl)thieno [3,2-b]thiophene)] (DPPDTT) are commonly used for OECTs because of their excellent semiconducting properties. However, it is challenging to achieve stretchable and high-performance OECTs based on hydrophobic P3HT and DPPDTT because of their limited ion penetration. Here, unprecedented stretchable high-performance OECTs based on P3HT and DPPDTT aerogels with crimpled porous structures are developed. They are achieved by a pre-stretching strategy combined with sol-gel and template methods. The porous structures of the aerogels with high porosities facilitate ion penetration and transport, leading to the enhanced transconductance of the aerogel-based OECTs compared with those of the dense counterparts. The crimpled porous structures endow the aerogels and OECTs with good stretchability and stretching stability. The stretchable OECT-based biosensors can detect trace amounts of ascorbic acid in complex samples such as sweat, saliva, serum, and fruit juice in real time. Besides, the OECTs can be applied as stretchable artificial synapses for neuromorphic simulation. This work provides a powerful strategy toward stretchable high-performance transistors and flexible electronics.