Alternating Current Electroluminescent (ACEL) Devices for Dynamic Intelligent Displays Controlled by Wireless Networks

Alternating current electroluminescent (ACEL) devices are recognized for their simple structure, uniform and soft light emission, tunable frequency, and broad wavelength range, making them suitable for diverse display and lighting applications. In this study, four types of inorganic ACEL devices with top-emission (TES), bottom-emission (BES), dual-emission (DES), and coplanar-emission (PES) configurations were fabricated using copper-doped zinc sulfide (ZnS:Cu) as the luminescent layer and barium titanate (BaTiO3) as the dielectric layer. The core novelty of this work lies in the systematic optimization of the full screen printing process for multi configuration inorganic ACEL devices, achieving independent substrate manufacturing on rigid (ITO glass) and flexible (ITO-PET, PI, cotton, and paper) substrates. In addition, we propose a PES-ACEL configuration with a polar liquid/solid interface excitation mechanism, breaking the traditional dependence of ACEL on dielectric layers and transparent electrodes and expanding substrate compatibility for special scenarios. All devices exhibited stable blue-green emission with a wavelength range of 480–550 nm, peaking at approximately 510 nm. Specifically, the BES-ACEL device demonstrated the highest performance, achieving a peak brightness of 141 cd/m2. The brightness of devices fabricated on various substrates increased monotonically with rising voltage (40–160 V) and frequency (100–400 Hz), highlighting excellent substrate independence and mechanical flexibility. The devices also withstood mechanical deformation, confirming their potential for wearable applications. Furthermore, to enhance functional versatility, an ACEL device was integrated with an STM32 microcontroller and a WiFi module to construct a dynamic display system. This system innovatively adopts an 8-channel relay module to connect the microcontroller and segmented “8” electrodes, realizing the conversion of 5 V DC input to 220 Vpp square wave output at 2 kHz and solving the problem of matching low-voltage control signals with high-voltage ACEL driving requirements. This system enables smartphone-based remote control for instantaneous switching of digital patterns (1–9). The wireless platform maintained stable illumination during dynamic operation, demonstrating a successful expansion of ACEL technology from basic lighting toward interactive human–machine interfaces.