Lateral organic light-emitting diode with field-effect transistor characteristics

We succeeded in observing bright electroluminescence (EL) from $1\mathrm{wt}\%$ -rubrene doped tetraphenylpyrene (TPPy) as an active layer in a lateral organic light-emitting diode structure that allowed field-effect transistor operation. This device configuration provides an organic light-emitting diode structure where the anode (source) and cathode (drain) electrodes are laterally arranged, providing us a chance to control the EL intensity by changing the gate bias. We demonstrated that TPPy provides compatible transistor and EL characteristics. Further, not only rubrene doping into the TPPy host but also adjusting the source-drain channel length significantly improved the EL characteristics. We observed a maximum EL quantum efficiency $\left({\eta }_{\mathrm{ext}}\right)$ of $\sim 0.5\%$ with a $\mathrm{Cr}∕\mathrm{Au}$ source $\left(S\right)$ -drain $\left(D\right)$ electrode and a slightly higher ${\eta }_{\mathrm{ext}}$ of $\sim 0.8\%$ with $S\text{-}D$ electrodes of $\mathrm{Mg}\mathrm{Au}∕\mathrm{Au}$ , $\mathrm{Al}∕\mathrm{Au}$ , $\mathrm{Cr}∕\mathrm{Y}\mathrm{Au}∕\mathrm{Au}$ , and $\mathrm{Mg}\mathrm{Al}∕\mathrm{Au}$ multilayers, aiming for simultaneous hole and electron injection.