A gate dielectric that enables high ambipolar mobilities in polymer light-emitting field-effect transistors

Polymer light-emitting field-effect transistors (LEFETs) require high and balanced electron and hole mobilities to achieve high current densities. Here we demonstrate a novel gate dielectric for polymer LEFETs that enables mobilities of 0.01cm2∕Vs for both electrons and holes. The low-k dielectric polycyclohexylethylene is placed in direct contact with the poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) semiconductor. A second dielectric layer comprising the high-k material poly(vinylidene fluoride-trifluoroethylene) is used to apply a high electric field onto the low-k dielectric layer. The attainable electron-hole recombination current in such optimized polymer LEFETs is measured and the implications for achieving electrically pumped lasing in a LEFET are discussed.