Color tuning and improved performance of poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1, 4-phenylenevinylene]-based polymer light emitting diode using cadmium selenide/zinc sulphide core shell uncapped quantum dots as dopants

摘要

A polymer light emitting diode (PLED) based on poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene]:CdSe/ZnS core shell uncapped quantum dots (QDs) was fabricated. It was observed that the presence of QDs in the polymer tunes the emission spectrum of the PLED as their QDs concentration increases to 10percent w/w and above. It was also found that the QDs present in the polymer improved the PLED luminance by approx20 times at a typical current density of 75 mA/cm~(2). This was attributed to the suppression of nonradiative electrostatic energy transfer from excitons to the metallic cathode due to the insertion of a high dielectric constant QD layer. Also, the presence of QDs layer between the active layer and the cathode shifts the recombination zone away from the cathode. This reduces the diffusion of radiative excitons into the metal electrode.