Three-armed imidazolium phenoxy ionic liquid as a novel crystal growth inhibitor for solid-state dye-sensitized solar cells

• TIPIL has a good amorphous feature and relatively low glass transition temperature.
• It can effectively prevent EMII from crystallization.
• It enhances the photovoltaic conversion efficiency of the ssDSSCs compared to the device without TIPIL.

A new three-armed imidazolium phenoxy ionic liquid (TIPIL) has been successfully designed, synthesized and characterized. The thermal property, amorphous feature and ionic conductivity of TIPIL were also investigated. 1-Ethyl-3-methylimidazolium iodide (EMII), a typical ionic conductor, could be effectively inhibited from crystallization by TIPIL, which has been characterized by several testing. Thus, as a crystal growth inhibitor, TIPIL was used into EMII based solid-state dye-sensitized solar cells (ssDSSCs). Compared with the reference device, the DSSC containing TIPIL showed improved photovoltaic conversion efficiency up to 5.37%, and displayed excellent long-term stability. These results provide us a feasible method to explore new crystal growth inhibitors for ssDSSCs.