Cross-Linkable Fluorene-Diphenylamine Derivatives for Electrochromic Applications

Area of Science:

• Materials Science
• Electrochemistry
• Organic Chemistry

Background:

• Development of advanced electrochromic materials is crucial for smart windows and displays.
• Arylamine-substituted fluorene derivatives offer tunable electronic and optical properties.

Purpose of the Study:

• To synthesize and characterize novel heat cross-linkable fluorene derivatives for multicolor electrochromic applications.
• To investigate the electrochromic performance and stability of cross-linked films and devices.

Main Methods:

• Synthesis of fluorene derivatives (FD and FDOMe) via Buchwald-Hartwig amination.
• Characterization using NMR, ESI-MS, X-ray diffraction, DSC, FT-IR.
• Spectroelectrochemical analysis of cross-linked films (FD-X, FDOMe-X).
• Fabrication and testing of electrochromic devices.

Main Results:

• Successful synthesis and characterization of FD and FDOMe with pendant vinyl groups.
• Thermally activated cross-linking confirmed for both derivatives.
• FD-X and FDOMe-X exhibited reversible redox behavior and multicolor electrochromism (colorless-yellow-dark cyan and colorless-brick red-blue, respectively).
• Good switching stability (>300 cycles) and low switching voltages (<1.3 V).
• Electrochromic devices showed low switching times (<30 s) and good optical contrast.

Conclusions:

• Heat cross-linkable fluorene derivatives are effective for creating stable, multicolor electrochromic systems.
• The synthesized materials demonstrate potential for practical applications in electrochromic devices.
• Tunable electrochromic properties achieved through molecular design and cross-linking.