Fig. 4: Mechanical properties of ultra-flexible ST-OPVs.
a Images of ultrathin ST-OPVs laminated into polymeric elastomer from pre-stretched condition (200% tensile strain) to compressed condition (0% tensile strain) with tensile strain steps of 50%. b 3D confocal microscope image of 100% tensile strained sample. c Top-view SEM image (left) of device surface at 100% tensile strain and enlarged image (right) indicating that bending radius below 1 µm. Changes in photovoltaic parameters of d, VOC, e ISC, f FF. g PCE under forward and backward compression. h Change in PCE of ST-OPVs under repetitive cycles of compression–release.
