Fabrication of Stacked Organic Electroluminescence Devices with a Combination of Spin Coating and Electrospray Deposition

A combination of spin coating and electrospray deposition (ESD) was applied for the fabrication of an organic light-emitting diode (OLED) with a stacked structure. Two kinds of polymer materials were used to fabricate a multilayered structure. One was poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV; Sigma-Aldrich) and the other was poly[2,5-di(hexyloxy)cyanoterephthalylidene] (CN-PPV; Sigma-Aldrich). With the addition of acetone to polymer material (MEH-PPV and CN-PPV) solution, smaller droplets were produced at the emitter resulting in thin-film fabrication under a dry condition. This condition was adopted for CN-PPV film deposition on MEH-PPV surface made by the spin coating method. The double-layered OLED obtained successfully emitted light at a bias voltage of 15 V. Layer-by-layer stacking of CN-PPV and MEH-PPV was confirmed by the UV-induced fluorescence spectrum. In case of the layer-by-layer structure, the obtained spectrum showed a linear combination of spectrum from MEH-PPV and CN-PPV.