Fig. 3: Characterization of the electrical performance of iRUM-s under mechanical deformation and solvent treatment.

a Device structure of a fully stretchable transistor with a bottom-gate top-contact configuration, W/L = 1000 μm/150 μm. b Representative transfer curves of a stretchable transistor with neat DPPTT film or iRUM-s as the semiconductor. c Evolution in mobility at different strains during single stretching, with charge transport parallel to stretching direction. d Evolution in mobility after multiple stretching-releasing cycles at 50% strain under strain released state, with charge transport parallel and perpendicular to stretching direction. Stress-strain (engineering) curves with a cyclic strain range of 10–70% for iRUM-s-3:1 (e) and iRUM-s-3:7 (f) films, where an iRUM-s film (35 nm thick) was supported on a thin PDMS substrate (2.4 μm thick). g Optical microscope images of IDTBT and iRUM-IDTBT after 500 stretching-releasing cycles at 50% strain under strain released state. h Changes in mobility of a neat IDTBT film and an iRUM-IDTBT film after multiple stretching-releasing cycles at 50% strain under strain released state. i Comparison of the cyclic durability in this study with previously reported results in the literature^{16,20,22,41,42,43,44} (spin-coated semiconductor films using insulating polymer dielectrics under strain released state without applying other engineering techniques, which reflects the intrinsic properties of semiconductors). j Curves of the peeling force per width of PDMS sheet versus displacement for BA rubber and PDMS. The higher peeling force between BA rubber and PDMS indicates the formation of interfacial crosslinking. k AFM height and phase images of iRUM-s-3:1 after soaking in various organic solvents (trichloroethylene, chloroform, chlorobenzene, and toluene) for 30 s. The surface roughness is extracted from the AFM height image.