Synergetic Strategy for Highly Efficient and Super Flexible Thick-film Organic Solar Cells

摘要

Efficient organic solar cells (OSCs) equipped with thick-film active layersand high flexibility are of great significance for industrial preparation andpractical applications. Herein, a ternary strategy coupled with a functionaladditive is employed to obtain efficient thick-film flexible OSCs. A novelpolymer donor PBB1-F with good planarity is synthesized as a third componentto optimize photon capture and molecular stacking. Meanwhile,a high dielectric constant polyarene ether (PAE) functional additive withstrong adhesion not only greatly improves exciton dissociation efficiency,but also acts as locking cage-like for effective enhancement of the mechanicalstability of active layer. As a result, the PM6:PBB1-F:Y6-BO-4Cl andPM6:PBB1-F:BTP-eC9 based ternary OSCs with PAE exhibit an efficiencyof 17.91 and 18.51 under rigid thin-film state, and perform better underthick-film state of rigid (16.40 and 16.84) and flexible (14.78 and14.95). Under the protection of the polymers, tight entanglement and cagelikePAE adhesion, the elongation at break of the active layer increases bymore than fourfold (27.3), and gives a super flexible thick-film OSCs thatmaintains more than 90 performance after 1000 bending cycles with adiameter of 10 mm. Overall, this work provides a new feasible scheme toeffectively solve thickness sensitivity and flexibility issues in the contextorganic photovoltaic applications.