High-Performance n-Type Stretchable Semiconductor Blends for Organic Thin-Film Transistors and Artificial Synapses

The design of high-performance stretchable n-type semiconductors is important in the construction of complementary circuits for flexible electronics. Herein, we propose a strategy by blending an electron transport-conjugated polymer poly(7,7′-difluoro-N,N′-bis(6-(trioctylsilyl)hexyl)-isoindigo-alt-(E)-1,2-bis(3,4-difluorothien-2-yl)ethene) (IID-SiC8) with a hole transport elastic block copolymer poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene]-block-hydrogenated hydroxyl-terminated polybutadiene (PBTTT-b-HTPB) to achieve stretchable semiconductors with high electron mobility and synaptic function in organic thin-film transistors. The p-type segments of PBTTT-b-HTPB behave as trap centers for minority holes to improve the overall performance of n-channel transistors or function as hole-trapping/detrapping sites to create memory windows, depending on the blending ratio. By adding 25 wt % PBTTT-b-HTPB, the blend film exhibits mobility up to 1.71 cm2 V–1 s–1, which is the highest value of n-type stretchable semiconductors so far, together with a high on/off ratio of 106–107. Notably, the mobility of the nanofilm remains almost unchanged after 1000 stretching cycles under 100% strain due to good fatigue resistance. By adding 75 wt % PBTTT-b-HTPB, synaptic functions were realized as a response to gate voltage pulse. Neuromorphic computing simulation constructed with this synaptic transistor can conduct pattern recognition at high accuracy up to 85.00%. Our multipurpose strategy of employing a single matrix that can simultaneously tune mechanical properties and electrical functions offers the prospect of high-performance stretchable functional optoelectronic devices.