Solution-Processable, High-Performance Flexible Electroluminescent Devices Based on High-k Nanodielectrics

Abstract

Flexible alternating-current electroluminescent (ACEL) devices have attracted considerable attention for their ability to produce uniform light emission under bent conditions and have enormous potential for applications in back lighting panels, decorative lighting in automobiles, and panel displays. Nevertheless, flexible ACEL devices generally require a high operating bias, which precludes their implementation in low power devices. Herein, solution-processed La-doped barium titanate (BTO:La) nanocuboids (≈150 nm) are presented as high dielectric constant (high-k) nanodielectrics, which can enhance the dielectric constant of an ACEL device from 2.6 to 21 (at 1 kHz), enabling the fabrication of high-performance flexible ACEL devices with a lower operating voltage as well as higher brightness (≈57.54 cd m−2 at 240 V, 1 kHz) than devices using undoped BTO nanodielectrics (≈14.3 cd m−2 at 240 V, 1 kHz). Furthermore, a uniform brightness across the whole panel surface of the flexible ACEL devices and excellent device reliability are achieved via the use of uniform networks of crossaligned silver nanowires as highly conductive and flexible electrodes. The results offer experimental validation of high-brightness flexible ACELs using solution-processed BTO:La nanodielectrics, which constitutes an important milestone toward the implementation of high-k nanodielectrics in flexible displays.