Non-Volatile Polymer Electroluminescence Programmable with Ferroelectric Field-Induced Charge Injection Gate

Electroluminescence (EL) of organic and polymeric fluorescent materials programmable in the luminance is extremely useful as a non-volatile EL memory with the great potential in the variety of emerging information storage applications for imaging and motion sensors. In this work, a novel non-volatile EL memory in which arbitrarily chosen EL states are programmed and erased repetitively with long EL retention is demonstrated. The memory is based on utilizing the built-in electric field arising from the remnant polarization of a ferroelectric polymer which in turn controls the carrier injection of an EL device. A device with vertically stacked components of a transparent bottom electrode/a ferroelectric polymer/a hole injection layer/a light emitting layer/a top electrode successfully emits light upon alternating current (AC) operation. Interestingly, the device exhibits two distinctive non-volatile EL intensities at constant reading AC voltage, depending upon the programmed direct current (DC) voltage on the ferroelectric layer. DC programmed and AC read EL memories are also realized with different EL colors of red, green and blue. Furthermore, more than four distinguishable EL states are precisely addressed upon the programmed voltage input each of which shows excellent EL retention and multiple cycle endurance of more than 10⁵ s and 10² cycles, respectively.