Field induced electroluminescence of either organic or inorganic fluorescent materials under alternating current (AC) has been of great attention as a potential candidate for next generation displays, lightings and sensors. Unique device architecture in which an emitting layer is separated with an insulator from electrode offers a new platform for designing and developing a variety of types of ELs. Here, we demonstrate high-performance field-induced AC polymer electroluminescence (AC-PEL) devices with high brightness, high efficiency and color-tunability. We also present a non-volatile EL memory in which arbitrarily chosen EL states are programmed and erased repetitively with long EL retention. Our memory is based on utilizing the built-in electric field arising from the remanent polarization of a ferroelectric polymer which in turn controls the carrier injection of an AC-PEL device. 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 R, G and B. Finally, we show that simultaneous sensing and visualization of the conductive substance is achieved when the conductive object is coupled with the light emissive material layer on our novel parallel-type AC-PEL device. A variety of conductive materials can be detected regardless of their work functions, and thus information written by a conductive pen is clearly visualized, as is a human fingerprint with natural conductivity.
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