Abstract: [6,6]-Thienyl-C61-butyric acid ester derivatives with different alkyl chains at the 5-position of thiophene ring(TCBM-Cn, n-represents the number of carbon atom in the alkyl chain) are introduced as compatibilizers in poly(3-hexyl thiophene)/[6,6]-phenyl-C61-butyric acid methyl ester(P3HT/PCBM) blend films. The effect of different crystalline ability of TCBM-Cn on the thermal stability and the crystallization of P3HT in blend films is discussed. Although it is difficult to completely prevent the aggregation of fullerene, a small amount of good crystalline compatibilizer can enhance the crystallization of P3HT. To the contrary, poor crystalline compatibilizer can completely prevent the aggregation of fullerene, but more compatibilizers are required to improve the crystallization of P3HT.

Key words: compatibilizers, polythiophene, fullerene, morphology, crystallization