Toward the ideal organic light-emitting diode. The versatility and utility of interfacial tailoring by cross-linked siloxane interlayers

Small molecule and polymer organic light-emitting diodes (OLEDs) show promise of revolutionizing display technologies. Hence, these devices and the materials that render them functional are the focus of intense scientific and technological interest. The archetypical multilayer OLED heterostructure introduces numerous chemical and physical challenges to the development of efficient and robust devices. It is demonstrated here that robust, pinhole-free, conformal, adherent films with covalently interlinked structures are readily formed via self-assembling or spin-coating organosilane-functionalized molecular precursors at the anode-hole transport layer interface. In this manner, molecularly engineered hole transport and hydrocarbon anode functionalization layers can be introduced with thicknesses tunable from the angstrom to nanometer scale. These investigations unequivocally show that charge injection and continuity at the anode-hole transport layer interface, hence OLED durability and efficiency, can be substantially enhanced by these tailored layers.