Flexible Multi-Colored Electrochromic and Volatile Polymer Memory Devices Derived from Starburst Triarylamine-Based Electroactive Polyimide

Flexible multi-colored electrochromic and volatile memory devices are fabricated from a solution-processable electroactive aromatic polyimide with starburst triarylamine unit. The polyimide prepared by the chemical imidization was highly soluble in many organic solvents and showed useful levels of thermal stability associated with high glass-transition temperatures. The polyimide with strong electron-donating capability possesses static random access memory behavior and longer retention time than other 6FDA-based polyimides. The differences of the highest-occupied and lowest unoccupied molecular orbital levels among these polyimides with different electron-donating moieties are investigated and the effect on the memory behavior is demonstrated. The polymer film shows reversible electrochemical oxidation and electrochromism with high contrast ratio both in the visible range and near-infrared region, which also exhibits high coloration efficiency, low switching time, and the outstanding stability for long-term electrochromic operation. The highly stable electrochromism and interesting volatile memory performance are promising properties for the practical flexible electronics applications in the future.