Surface interpenetration between conducting polymer and PET substrate for mechanically reinforced ITO-free flexible organic solar cells

A surface-interpenetrated conducting polymer, PANI:CSA on plastic substrate, especially cheap PET significantly boosts mechanical properties for outstanding performance as an ITO-free organic electrode in flexible organic solar cells and exhibits best performance of an average power conversion efficiency of 3.5±0.2% under 100 mW/cm2 illumination, with a short-circuit current density of 8.7 mA/cm2, an open-circuit voltage of 0.83 V, and a fill factor of 0.49 comparable to conventional organic solar cells made with ITO electrodes on glass or PET.