Bifunctional Interactive Light‐Emitting Devices Based on Hydrogel Microspheres

Abstract Interactive sensing technologies have great potential applications in the fields of smart homes, medical monitoring, and autonomous driving. However, existing hydrogel‐based alternating current electroluminescent (ACEL) devices suffer from inadequate stability. To address this limitation, an inorganic AC electroluminescent pressure sensor based on hydrogel microspheres (HMPs‐ACEL) is developed using a reverse‐phase polymerization emulsification method combined with a silkscreen printing process. The main structure of this sensor includes an HMP layer sensitive to temperature, humidity, and pressure, a phosphor layer (PL), a dielectric layer (DL), and a fork finger electrode layer (EL). The incorporation of 3MLiCl@HMPs (0.1–0.2 wt.% PEDOT: PSS) significantly enhances the performance of the device. The free water content within the HMPs exceeds 60% of the total water content, resulting in a resistivity as low as 1.95 Ω cm and a maximum compressive strength of 12 MPa. The ACEL device featuring 3 MLiCl@HMPs (0.1–0.2 wt.% PEDOT: PSS) as the interaction layer achieves optimal brightness at 160 V and the highest light‐emitting efficiency at 140 V. These properties make the HMPs‐ACEL device one of the most efficient and cost‐effective solutions available, holding significant potential for applications in environmental monitoring and remote pressure detection.