Blue electroluminescent device based on a conjugated polymer

Polyparaphenylene (PPP) thin (≈0.5 μm) layers were investigated in order to realize a blue-light-emitting tunneling structure (LETS). The LETS consists of PPP confined between an indium/tin oxide (ITO) and an Al contact. Blue-light emission at room temperature occurred if a negative voltage exceeding 10 V was applied to the Al electrode. It is demonstrated that the device function is based on a field induced, tunneling assisted, radiative recombination process. Blue LETS are of considerable physical and technical interest due to the lack of a satisfactory material for such a device realization up to now.