Aromatic Solvent-Mediated Co-Crystallization for Transferred Chiroptical Transitions in Chiral Binaphthyl /π-Conjugated Polymer Hybrid Thin Films

Recently, chiral optoelectronic materials capable of interacting with circularly polarized light (CPL) gains significant attention as a key technology for propelling next-generation optoelectronic technologies. Among the various chiroptical nanomaterials, π-conjugated polymers (chiral π-CPs), leading advancement in the field of organic electronics, become a promising candidate to extend the era of future chiral optoelectronics. As a unique and promising strategy for impartment of the chiroptical activity in π-CPs, blending with chiral small molecules (π-CPs/chiral-SM hybrids) has attracted significant research interest, enables the integration of numerous achiral π-CPs with diverse optical and electrical properties and the strong chiral activity of small molecules. Here, we propose a versatile strategy for fabricating π-CP/chiral-SM hybrid films via co-crystallization-mediated chirality transfer. The primary finding is that optical chirality transfer from 1,1’-binaphthyl–2,2’-diamine (BN), a representative chiral inducer, to various achiral π-CPs, including non-fluorene π-CPs, is achieved by blending the π-CPs with BN using aromatic organic solvents. This results in hybrid films exhibiting chiroptical responses at the π-CPs' main electronic absorption bands ranging from UV to near-IR range. In-depth studies on the morphology and crystalline structure of a hybrid system of poly(3-hexylthiophene) (P3HT) and BN show a characteristic lamellar structure where π-CPs co-crystallize with chiral BN molecules, facilitated by aromatic solvent-assisted π–π interactions.As a proof-of-concept for the feasibility of the optoelectronic devices, we demonstrate chiroptical photodiodes based on π-CP/chiral-SM hybrid films and printed micropatterns, exhibiting a distinguishable photocurrent response to the direction of circularly polarized light.