Fig. 4

Thermal properties of bio-based SEP for flexible optoelectronics. a Linear thermal expansion curves of SUPERBIO and BPA-SEP films (inset: an enlarged part of the graph). b (Top) Photograph and (bottom) light transmission spectra of AgNW-coated SUPERBIO film. c Sheet resistance of AgNW-coated SUPERBIO film at different bending radii. d Comparison of sheet resistance changes of AgNW-coated SUPERBIO and BPA-SEP after thermal annealing at 300 °C for 1 h. Heat resistant operation of LED on the AgNW-coated SUPERBIO and BPA-SEP films at 300 °C, shown as time-lapse photograph over 1 h (Supplementary Movie 3). e Schematic illustration of flexible OLED fabrication in which SUPERBIO endured 250 °C thermal processes. f Photographs of (top) the fabricated OLED and (bottom) its electroluminescence operation with the applied voltage of 8 V under bending. The recycling of the SUPERBIO electrode. g Photograph (inset) and FE-SEM image of AgNW-coated SUPERBIO film. h Electrode dissolved in DMAc was filtered using a Nylon syringe-filter. Then, the filtered solution was casted into a transparent free-standing film. i Photograph (inset) and FE-SEM image of the resultant recycled SUPERBIO film