Large [6,6]-phenyl C61 butyric acid methyl (PCBM) hexagonal crystals grown by solvent-vapor annealing

•Large PCBM single crystals with >150 μm in size were formed using SVA.•Influences of substrate and solvent vapor for PCBM crystal growth was investigated.•Our method was used for a spontaneous formation of PCBM and C8-BTBT crystals.

We propose that solvent-vapor annealing is an efficient method for fabricating large [6,6]-phenyl C61 butyric acid methyl (PCBM) single crystals. The morphology and size of PCBM crystals are influenced by different substrates and annealing solvents. Hexagonal PCBM crystals >150 μm in size were obtained when crystallization was performed on bare SiO2 substrate under the saturated vapor of chloroform for annealing. The proposed method was also applied to a bi-component system, which led to the spontaneous formation of PCBM and dioctylbenzothienobenzothiophene single crystals.

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