Microstructure formation in molecular and polymer semiconductors assisted by nucleation agents

Treat, N.D.; Malik, J.A.N.; Reid, O.; Yu, L.Y.; Shuttle, C.G.; Rumbles, G.; Hawker, C.J.; Chabinyc, M.L.; Smith, P.; Stingelin, N.
Nat. Mater.
12, 628-633

Additives, including nucleating agents, have been used to regulate the solidification process of (semi-)crystalline polymer solids and thus control both their crystallite dimensions and shape. Here, we demonstrate that minute amounts (0.1–1 wt%) of commercially available nucleating agents can be used to efficiently manipulate the solidification kinetics of a wide range of organic semiconductors—including poly(3-alkylthiophene)s, the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and 6,13-bis(triisopropyl-silylethynyl) (TIPS) pentacene—when processed from the melt, solution or solid state, without adversely affecting the semiconductors’ electronic properties. Heterogeneous nucleation increases the temperature of and rate of crystallization of poly(3-alkylthiophene)s, permits patterning of crystallites at pre-defined locations in PCBM, and minimizes dewetting of films of TIPS-pentacene formed by inkjet printing. Nucleating agents thus make possible the fabrication of thin-film transistors with uniform electrical characteristics at high yield