Memory devices based on lanthanide (Sm³⁺, Eu³⁺, Gd³⁺) complexes

Memory effects in single-layer organic light-emitting devices based on Sm³⁺, Gd³⁺, and Eu³⁺ rare earth complexes were realized. The device structure was indium-tin-oxide (ITO)/3,4- poly(ethylenedioxythiophene)-poly(styrene-sulfonate) (PEDOT)/Poly(N-vinyl carbazole) (PVK): rare earth complex/LiF/Ca/Ag. It was found experimentally that all the devices exhibited two distinctive bistable conductivity states in current-voltage characteristics by applying negative starting voltage, and more than 10⁶ write-read-erase-reread cycles were achieved without degradation. Our results indicate that the rare earth organic complexes are promising materials for high-density, low-cost memory application besides the potential application as organic light-emitting materials in display devices.