Thermoplastic elastomer enhanced interface adhesion and bending durability for flexible organic solar cells

Stable interface adhesion and bending durability of flexible organic solar cells(FOSCs)is a basic requirement for its real application in wearable electronics.Unfortunately,the device performance always degraded during continuous bending.Here,we revealed the weak interface adhesion force between MoO_(3) hole transporting layer(HTL)and the organic photoactive layer was the main reason of poor bending durability.The insertion of an interface bonding layer with a thermoplastic elastomer,polystyrene-blockpoly(ethylene-ran-butylene)-block-polystyrene(SEBS)effectively improved the interface adhesion force of MoO_(3) HTL and the active layer and decreased the modulus,which ensured higher than 90%of the initial efficiency remaining after 10000 bending.Meanwhile,the FOSCs gave an efficiency of 14.18%and 16.15%for the PM6:Y6 and PM6:L8-BO devices,which was among the highest performance of FOSCs.These results demonstrated the potential of improving the mechanical durability of FOSCs through thermoplastic elastomer interface modification.