Interfacial Engineering of Quantum Dot-Decorated FeOOH Coupled with TiO ₂ Particles for Environmentally Adaptive and Energy-Efficient Electrophoretic Displays

Developing outdoor displays that combine low power consumption with high visibility remains a major challenge for sustainable information technologies. Electrophoretic displays (EPDs) are reflective and energy-efficient but suffer from poor color saturation, limited brightness, and the lack of nighttime emissive capability. Herein, we report that functional composite electrophoretic particles, denoted as FeOOH@QD, are prepared by grafting green CdZnSeS/ZnS quantum dots (QDs) onto FeOOH pigment particles via a surface-initiated polymerization. The FeOOH@QD particles exhibit excellent charge stability and high color purity, as well as dual-mode optical behavior, showing vivid green reflection under daylight and bright green fluorescence under 365 nm UV excitation. By integrating these particles with modified white TiO2–KH570–PLMA electrophoretic particles, a QD-enhanced electrophoretic display (QDEPD) is fabricated. The QDEPD demonstrates rapid switching speeds (210–250 ms at ±30 V), high contrast ratios (3.6 in reflection mode and 22.6 in emission mode), long-term bistability with image retention over 24 h without power, and excellent cycling durability. Importantly, the dual-mode QDEPD operates without backlight under ambient light and requires only intermittent low-voltage driving, greatly reducing power consumption. By combining reflection and emission modes, the QDEPD enables environment-adaptive and energy-efficient viewing, highlighting its potential for sustainable outdoor display technologies.