Electrochromic Devices Based on 2D MoO_3-/PEDOT:PSS Composite Film with Boosted Ion Transport

Area of Science:

• Materials Science
• Nanotechnology
• Electrochemistry

Background:

• Electrochromic materials are crucial for smart windows and displays due to their optical modulation capabilities.
• Two-dimensional (2D) molybdenum oxide (MoO₃) nanoflakes offer potential for electrochromic devices due to their high surface area and layered structure.
• Challenges include efficient preparation of 2D MoO₃ nanoflakes and improving their ionic kinetics for better performance.

Purpose of the Study:

• To develop an efficient top-down method for preparing thin 2D MoO₃ nanoflakes.
• To enhance the electrochromic performance of 2D MoO₃ nanoflakes by combining them with a conductive polymer.
• To investigate the impact of improved ionic and electronic conductivity on electrochromic properties.

Main Methods:

• A thiourea-assisted exfoliation procedure was used to produce thin 2D MoO₃ nanoflakes.
• Electrophoretic deposition was employed to combine MoO₃ nanoflakes with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS).
• The ionic diffusion coefficient and charge transport resistance of the composite films were measured.

Main Results:

• The thiourea-assisted method increased the yield and reduced the thickness of 2D MoO₃ nanoflakes.
• The 2D MoO₃/PEDOT:PSS composite films showed a high diffusion coefficient (3.09 × 10^-10 cm² s^-1) and low resistance (33.7 Ω).
• The composite films achieved fast switching speeds (5-7 s), high coloration efficiency (87.1 cm² C^-1), and significant transmittance modulation (65%).

Conclusions:

• The study successfully demonstrated a feasible method for preparing high-quality 2D MoO₃ nanoflakes.
• Combining 2D MoO₃ nanoflakes with PEDOT:PSS significantly enhances electrochromic performance.
• This work highlights the potential of 2D MoO₃ nanoflakes in advanced electrochromic applications and inorganic-organic composite optimization.