High-efficiency organic solar cells processed from a halogen-free solvent system

    abstract：

           The use of non-halogenated solvents for the green manufacture of high-efficiency organic solar cells (OSCs) is important for

their future application. However, the power conversion efficiency (PCE) of the non-halogenated solvent processed OSCs is

generally lower than their halogenated counterpart due to the poor film microstructure caused by the solubility issue. Herein, we

propose a halogen-free solvent system to optimize film microstructure of the photovoltaic blend based on the polymer donor D18

and small-molecule acceptor (SMA) L8-BO towards high-efficiency OSCs. The solvent system is consisted of a main solvent

carbon disulfide and an additive paraxylene, where the former ensures the good solution-processability and promotes the solution

aggregation of L8-BO, and the latter can finely control the phase-separation process by selectively dissolving the SMA. This

solvent combination robustly produces a high-quality active layer, i.e., the bicontinuous networks of donor and acceptor with

nano-sized phase-separation and strong π-π stacking. With the effective charge generation, transport and collection, the resulting

device from the non-halogenated solvent system shows a high PCE of 17.50%, which is comparable to that of the device

prepared from the halogenated solvent chloroform (ca. 17.11%). This article proposes a new strategy for the green fabrication of

high-efficiency OSCs to accelerate their industrialization

High-efficiency organic solar cells processed from a halogen-free solvent system | SpringerLink