High performance light emitting transistors

Solution processed light emitting field-effect transistors (LEFETs) with peak brightness exceeding $2500\mathrm{cd}∕{\mathrm{m}}^2$ and external quantum efficiency of 0.15% are demonstrated. The devices utilized a bilayer film comprising a hole transporting polymer, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-$b$ ] thiophene) and a light emitting polymer, Super Yellow, a polyphenylenevinylene derivative. The LEFETs were fabricated in the bottom gate architecture with top-contact $\mathrm{Ca}∕\mathrm{Ag}$ as source/drain electrodes. Light emission was controlled by the gate voltage which controls the hole current. These results indicate that high brightness LEFETs can be made by using the bilayer film (hole transporting layer and a light emitting polymer).