프러시안 블루-아연 전극 기반 자가 방전 전기변색 소자

Abstract

Electrochromic (EC) devices, which can reversibly change their optical properties through redox reactions under electrical stimulation, hold great promise for energy-efficient displays and smart windows. However, conventional EC systems require continuous external power to maintain their optical states and often suffer from limited visibility in low-light conditions. To address these issues, we developed a self-discharging electrochromic device using Prussian Blue (PB) and zinc (Zn) electrodes. Leveraging the significant redox potential difference between PB and Zn (~1.47 V), the device enabled spontaneous color changes (self-bleaching) without external voltage during discharge and rapidly reverted to its colored state when a 1.5 V charging voltage was applied. The PB-Zn device exhibited a high optical modulation (ΔT = 54.1% at 630 nm), approximately 40% better than single PB electrodes. In addition, we fabricated a display prototype with patterned PB electrodes and phosphorescent coating to enhance nighttime visibility. The phosphorescent layer enabled persistent luminescence without power in darkness, enabling 24-hour visibility. This self-discharging electrochromic system combined with phosphorescent coating offers a promising approach for energy-autonomous smart displays and information devices requiring high visibility with minimal power consumption.