The Phase I objective of this project is to demonstrate flexible light- emitting-diodes (LEDs) comprised of novel conjugated polymer/rare earth blends. Our preliminary studies, supported by the literature data on organic electroluminecsence (EL) devices indicate that the spectrally broad luminescence from a conjugated polymer can be converted into a nearly monochromatic light by small addition of a rare earth ion. This discovery creates an opportunity for fabrication of spectrally pure red-emitting LEDs, hence eliminating one of the remaining obstacles in the commercialization of full-color plastic displays.In the first part of Phase I we focus on the chemistry of europium organic complexes whose optical properties need to be optimized in order to assure an efficient energy transfer. Feedback to the synthetic efforts will be provided by on-line photoluminescence (PL) studies aimed toward selection of the most promising polymer/rare earth blends. These will be used for fabrication of the red-emitting LEDs on both rigid and flexible substrates. The performance of the LEDs, including I-v response, spectral purity, quantum efficiency, stability, and reproducibility, will be rigorously tested in order to demonstrate the feasibility of the Phase IT program