The introduction of a third component into the binary system to construct a ternary architecture is widely applied to improve the power conversion efficiency (PCE) of organic solar cells (OSCs). Herein, a small molecule donor, SM1, was introduced into the PM6:Y6 binary system where a high PCE of up to 16.55% was achieved after the addition of 15 wt% of SM1 in the donors with an open-circuit voltage (V_oc) of 0.831 V, a short-circuit current density (J_sc) of 25.7 mA cm⁻², and a fill factor (FF) of 77.5%, which was much higher than that of the PM6:Y6 binary systems (15.75%), presenting a V_oc of 0.845 V, a J_sc of 25.3 mA cm⁻², and a FF of 73.7%. The introduction of SM1 improved the charge extraction, exciton dissociation, and blend of the morphology while effectively reducing bimolecular recombination. As a result, the J_sc and FF of the ternary devices greatly improved. This study presents an effective method to improve the PCE by adopting a ternary strategy, while at the same time, promoting a simple fabrication technology.

An in-situ cross-linkable monomer is carefully developed into blend films to finely manipulate the molecular packing, crystallization and nanomorphology during film formation. As a result, stabilized PCEs of 19.84% for the rigid device and 18.32% for flexible organic solar cells are achieved.

Fabrication of flexible transparent electrodes (FTEs) is one of the core technologies in the field of flexible electronics. Among multiple choices of FTEs, poly(3,4-ethylenedioxythiophene):poly(styrene-sulfonic acid) (PEDOT:PSS) has shown its promising application in roll-to-roll manufacturing. A simple yet effective method for substantially boosting the conductivity of these conducting polymer films without causing large-domain aggregations is by adding ethylene glycol (EG) as dopant. Herein, we investigated in detail the effects of the secondary solvent of ethylene glycol (EG) on the optical and electrical characteristics of PEDOT:PSS films. The modified PEDOT:PSS FTEs were deposited using drop-coating techniques as it had greater compatibility for large-area samples than the conventional spin-coating method did. The 6% EG-doped PEDOT:PSS FTE via drop-coating method achieved a high figure of merit (FoM) value of 47.24 and the devices fabricated using the optimal PEDOT:PSS FTE yielded a high power conversion efficiency (PCE) of 8.89%, mostly attributed to the modified PEDOT:PSS films that had excellent optical and electrical characteristics with low surface roughness. These results suggested that EG-doping could effectively boost the conductivity of PEDOT:PSS films and that the modified PEDOT:PSS FTE is suitable for roll-to-roll manufacturing in the future.