Flexible bioelectronic devices, which can directly detect various external stimuli or biosignals and communicate the information to the users, have been broadly investigated due to the increasing demand for wearable devices. Among them, alternating-current electroluminescence (ACEL) devices are proposed as sensitive sensing systems for various targets, such as fingerprints. Herein, we propose a method for preparing high-performance ACEL devices by using an Ag electrode, polyethylene terephthalate (PET) substrate, FKM/EMI ionogel, and ZnS:Cu/BaTiO