In this work we present an all solution processing scheme for the fabrication of the three primary colors, (R–G–B), emitting organic light-emitting diodes (OLEDs) via efficient color tuning of a blue organic semiconducting (OSC) thin film, in particular the poly[9,9-di-(2′-ethylhexyl)fluorenyl-2,7-diyl] (PF), in which different color fluorescent emitters are dispersed to define the final emitting color and thus to simplify the different color device fabrication. The transmission speed of the fabricated OLEDs was also examined for possible application in interactive telecommunications. To increase the response speed of the different color devices we altered both the device geometry and the electron injection efficiency. To this end we increased the emissive layer thickness and decreased the device emissive area and we also performed engineering of the cathode interfaces through the incorporation of solution processed porphyrin interlayers in order to lower the electron injection barrier height. The final devices exhibited improved operational characteristics and, consequently, modulation speeds.