High-k Polymer Nanocomposites as Gate Dielectrics for Organic Electronics Applications

Motivated by the recent development in organic electronics such as organic field effect transistors (OFETs), printed electronics,.. etc., these emerging technologies have received increasing attention. In addition to the organic semiconductor, gate dielectrics for organic electronics have been the focus of recent R&D attention as well. For this application, the dielectric materials should ideally be compatible with flexible substrate, solution processible, and exhibit larger capacitance to increase the drain current while operating at low biases. Complementary to conventional high dielectric constant (k) inorganic materials and those readily accessible and solution processible polymer materials, polymer/inorganic hybrid films which could be deposited by spin-coating are well suited to provide a better solution. In this study, a solution processible nanocomposite containing benzocyclobutene (BCB) and barium titanate (BT) nanoparticles was developed. Dielectric and electrical properties of the as-prepared BT nanocomposites were investigated, k values of 50 and capacitance density of 19 nF/cm² was achieved for a 50 vol.% BT loading. And the dielectric breakdown strength could be maintained 1.65 MV/cm, which is even higher than that of some other polymers themselves. The preliminary result of the electrical output of OFET prototype incorporating high k BT/BCB nanocomposite as gate insulator layer shows that the OFET can be operated at very low voltage. This demonstrates the feasibility of using high k BT/BCB nanocomposite as gate dielectric insulator in the OFET.