Flexible Multi-Mode Electrochromic Displays for Human Motion Monitoring and Pattern Display in Dark Environments

Flexible electrochromic displays (ECDs) demonstrate low energy consumption, good readability, and high color contrast. However, their performance deteriorates in dark environments due to the reliance on environment light. Herein, we propose a flexible multi-mode electrochromic display (FMECD), which is designed to effectively integrate electrochromism-photoluminescence-mechanoluminescence (EC-PL-ML) functionalities. The PL and ML serve as backlight to simulate a natural light condition for display in dark environment. The function is realized by incorporating tannic-acid-modified polydimethylsiloxane (PDMS), incorporated with ZnS: Cu phosphor as a backlight, onto which patterned tungsten trioxide (WO₃)-EC devices are applied. The FMECD shows a large optical modulation of 75.8% and maintains robust EC performance with a reflection retention of 86% after 200 stretching cycles, and 91.5% after 500 bending cycles. Notably, compared to commercial organic light-emitting diode (OLED) displays, the FMECD significantly reduces energy consumption from 172.2 Wh m^-2 to 0.0075 Wh m^-2. As a proof of concept, we demonstrate the functionality of the FMECD as a patterned display that visualizes various motion states of different body parts in multiple scenarios of dark environments, advancing the development of wearable intelligent displays for human motion monitoring and signal patterning.