Au is not a suitable cathode material of organic light-emitting device because of its high work function resulting in poor electron injection. However, in present work, it is found that the performance of Au-cathode OLEDs can be efficiently improved by introducing a LiF buffer layer and with its optimal thickness can even be comparable to that of conventional Alcathode device. The relationship between the thickness of LiF layer and the performance improvement is investigated. The experimental results indicate a quite different mechanism of LiF thin layer from that of Al-cathode device, which is not chemicalreaction-mechanism-dominant. Other insulator material buffer layers such as Al 2 O 3 and BCP are also investigated.

Single-layer organic memories made of organic material with good conductance have been characterized. Asymmetrical bistable behaviors under biases of opposite polarities are observed for devices with asymmetric electrodes. It is experimentally confirmed that a close correlation exists between the conductivity of the organic layer and the asymmetric bistability of the device under opposite biases. Inserting a block layer or thickening the organic layer will result in negative differential resistance under positive biases, leading to reversible symmetrical bistability. The phenomena are ascribed to the presence of filamentary microconducting channels in the organic layer.

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The interfaces of poly (p -phenylene vinylene) and fullerene derivatives with Al, LiF, and Al/LiF studied by secondary ion mass spectroscopy and x-ray photoelectron spectroscopy: Formation of AlF 3 disproved

The effect of electric field and temperature on bistable characteristics of indium tin oxide/tris-(8-hydroxyquinoline) aluminum (Alq3)/aluminum (Al) device has been investigated. The switching time, during which the device turns from a high resistive (OFF) state to a low resistive (ON) state, increases with decreasing field and temperature. The observed phenomena are accounted for by a phenomenological model that metallic nano-tips may evolve under the influence of the electric field and temperature.