Compositional Optimization of Sputtered WO₃/MoO₃ Films for High Coloration Efficiency

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Mixed metal oxides, such as molybdenum trioxide (MoO3) and tungsten trioxide (WO3), are promising materials for electrochromic (EC) devices.
• Optimizing the composition of these mixed oxides is crucial for achieving desired EC performance.

Purpose of the Study:

• To determine the optimal composition of mixed MoO3 and WO3 thin films for the best electrochromic properties.
• To investigate the electrochromic characteristics of the full composition range of the binary MoO3/WO3 system.

Main Methods:

• Thin films of mixed MoO3 and WO3 were fabricated using reactive magnetron sputtering onto ITO-covered glass.
• A combinatorial material synthesis approach was employed to cover the entire composition range.
• Electrochromic properties were evaluated by measuring transmittance and current in an organic electrolyte cell.

Main Results:

• The study identified a characteristic maximum in coloration efficiency at approximately 60% MoO3.
• The combinatorial approach enabled precise localization of this optimal composition with 5% accuracy.
• Mixed MoO3/WO3 thin films exhibited significant electrochromic behavior.

Conclusions:

• The optimal composition for enhanced electrochromic performance in MoO3/WO3 thin films was determined to be around 60% MoO3.
• Combinatorial synthesis is an effective strategy for rapidly identifying optimal material compositions for electrochromic applications.
• Further research can leverage these findings for developing advanced EC devices.