The performance of organic LEDs can be improved by modifying the organic thin film-electrode interface. Here is reported the use of layer-by-layer, self-limiting chemisorptive siloxane self-assembly techniques to deposit layers of the capping agent octachlorotrisiloxane between an indium tin oxide anode layer and the hole transport layer. Such techniques can yield nearly pinhole-free dielectric layers with angstrom-level control over total dielectric layer thickness. Examination of the physical and electronic properties of the resulting devices shows that the external quantum and luminous efficiencies of the LED are significantly enhanced after the introduction of the dielectric layers.