Solution-processed polyfluorene–ZnO nanoparticles ambipolar light-emitting field-effect transistor

We report on a solution-processed polyfluorene (PFO)–ZnO nanoparticles composite light-emitting organic field-effect transistor (LE-OFET). The behavior of absorption, photoluminescence spectra and electroluminescence intensity of the PFO:ZnO hybrid films with different concentration of ZnO nanoparticles is analyzed. By changing the PFO/ZnO nanoparticles concentration ratio the PFO:ZnO OFET shows either unipolar or ambipolar behavior of current–voltage characteristics and operates in the hole/electron accumulation mode with current saturation behavior. The field effect mobility of charge carriers depends on the ZnO concentration. For the ambipolar PFO:ZnO OFET with modest PFO/ZnO nanoparticles ratio (1:0.2), well balanced electron and hole mobility values at 300 K are ∼0021 and ∼0029 cm2/Vs, respectively, whereas for films with high ZnO concentration (1:1) the mobility (∼2 cm2/Vs) is close to that of polycrystalline ZnO. The ambipolar PFO:ZnO LE-OFET emits light at both positive and negative gate bias. The working mechanism of the PFO:ZnO LE-OFET is investigated.

Figure optionsDownload as PowerPoint slideHighlights
► We design a solution-processed polyfluorene - ZnO nanoparticles composite light-emitting organic field-effect transistors (LE-OFETs).
► By changing the PFO/ZnO nanoparticles concentration ratio these devices show either unipolar or ambipolar behavior of current-voltage characteristics.
► The ambipolar PFO:ZnO LE-OFET emits light at both positive and negative gate bias.