Estudo da interface Cu(2-x)Se/PEDOT:PSS/MEH-PPV

Abstract

In this work, a study was made of the Cu2-xSe/PEDOT:PSS/MEH-PPV interface, with measurements of Atomic Force Microscopy (AFM), electrical and optical. Copper (Cu) films were produced in different thicknesses with copper evaporation process on projector transparency (polyester, sold for laser printing). The films were then converted at different conversion times to produce the first layer of organic light-emitting diodes (OLEDs). The copper selenide layer (Cu2-xSe), responsible for injecting holes in the device, is a material with the potential to be an alternative to tin and indium oxide or fluorine-doped tin oxide, which are longer in the Marketplace. After the conversion of Cu to Cu2-xSe, layers of poly(3,4-ethylenedioxythiophene): poly(sulfonated styrene) (hole injector), poly(2-methoxy 5-(2'-ethyl-hexyloxy)) were deposited -1,4-phenylene-vinylene) (active layer) and finally Aluminum (electron injector). The AFM results made it possible to understand the surface morphology of the films after copper deposition, their thickness and the conversion to Cu2-xSe films and their thickness. To verify the purity of the films, measurements were taken by Energy Dispersive Spectroscopy, proving the purity in the evaporation and conversion processes of the films. With the electrical measurements, the sheet resistance values of the Cu2-xSe electrodes were obtained and it was verified that there is a conversion time for the device to operate with injection of charge carriers (holes) only by direct tunneling effect. This conversion time is 30 seconds for the 40 nm thick copper film.