A light-emitting device, which improves the light output of organic light emitting diodes (OLEDs), includes at least one porous metal or metalloid oxide light extraction layer positioned between the substrate and the transparent conducting material layer in the OLED. The index of refraction of the light extraction layer and the light scattering may be tuned by changing the pore size, pore density, doping the metal oxide, adding an insulating, conducting or semiconducting component, or filling the pores, for example. A method for forming the light-emitting device includes forming at least one light extraction layer comprising a porous metal or metalloid oxide on a substrate, for example, using atmospheric pressure chemical vapor deposition (APCVD), and subsequently, forming a transparent conducting material on the light extraction layer.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
 This invention was developed in conjunction with Battelle Memorial Institute, Pacific Northwest National Laboratory (PNNL), a U.S. Department of Energy (DOE) government research laboratory.