Semi-interpenetrating network of polymer semiconductor and tetrapod nanocrystal assemblies with balanced ambipolar transport

Abstract

Most organic semiconductors exhibit p-type electrical characteristics, whereas inorganic semiconductor nanocrystals typically possess n-type characteristics. Therefore, in principle, blending these two different materials can yield ambipolar transport for both electron and hole conduction if a percolation pathway for each charge carrier can be developed within the blended material. As the dimensions of these materials are on the nanometer scale, forming such a percolation pathway is challenging. Herein, we report a solution-processed method to construct an ambipolar channel by combining tetrapod-shaped CdSe nanocrystals and polythiophene. A fully percolated network of tetrapod CdSe nanocrystals were first produced by benefitting from the extended geometry of the nanostructure with four arms. The voids of the network were then filled with polythiophene, leading to a semi-interpenetrating network containing percolation pathways for both electrons and holes. A balanced ambipolar transport was achieved with electron and hole conductivities of 10.6 S/cm and 16.2 S/cm, respectively. The hybridization strategy for organic/inorganic semiconductors presented herein provides an innovative route to prepare solution-processable thin films for both electron and hole transport electronic devices.