Controlling Molecular Packing for Charge Transport in Organic Thin Films

Tuning of the packing mode, including the film morphology, molecular orientation, and phase state of chloroaluminum phthalocyanine (ClAlPc), is demonstrated, and yields optimal parallel and vertical channels for charge transport. On a pure SiO2 surface, the ClAlPc molecules lie flat and grow in the Volmer–Weber mode, resulting in a cone-array structure that is highly desirable for heterojunction organic solar cells and organic field emission. On an OTS-modified surface, the ClAlPc molecules stand obliquely and Stranski–Krastanov growth of a continuous and flat film occurs, which is suitable for organic transistors.