Solid additive for manipulating the lamellar-stacking phases of donor and π-stacking phases of acceptor and its recycling implementation in organic solar cells

Abstract

Volatile solid additives mainly manipulate the morphology of acceptor-rich domains within a bulk-heterojunction (BHJ) organic solar cell (OSC) system comprising donor and acceptor components. Contrary to such traditional paradigm, a 1,2,3,5-tetrachlorobenzene (TeCB) solid additive employed in this study affects the molecular ordering and crystallinity of both the donor- and acceptor-rich domains, resulting in the simultaneous reinforcement of the lamellar- and π-stacking phases in a D18-Cl:N3-based device. Consequently, after the addition of TeCB, electrical charge-related properties (e.g., carrier mobility, dissociation, collection, recombination, and extraction) are positively enhanced, ultimately improving the power conversion efficiencies (PCEs). Among the various BHJ OSC systems tested to demonstrate the universality of TeCB, the D18:L8-BO-based device exhibits an excellent PCE of up to 19.16%. Moreover, we, for the first time, demonstrate how the volatile solid additive can be retrieved and re-used while processing the device fabrication, giving a valuable guide to future OSC research toward the cost-effective and eco-friendly productions.