Dye-sensitized TiO2 solar cells using imidazolium-type ionic liquid crystal systems as effective electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Dye-sensitized solar cells (DSSCs) require efficient electrolytes for optimal performance.
• Ionic liquid crystals (ILCs) offer unique properties for advanced energy applications.
• Investigating charge transport in ILCs is crucial for enhancing DSSC efficiency.

Purpose of the Study:

• To evaluate the performance of a novel ionic liquid crystal (ILC) system (C(12)MImI/I(2)) as an electrolyte in DSSCs.
• To investigate the charge transport properties and conductivity of the ILC electrolyte in detail.
• To explore the fabrication of a quasi-solid-state ILC DSSC using a gelator.

Main Methods:

• Utilized a novel ionic liquid crystal (ILC) system (C(12)MImI/I(2)) with a smectic A phase as a DSSC electrolyte.
• Evaluated exchange reaction-based diffusion coefficients (D(ex)) to assess charge transport.
• Fabricated a quasi-solid-state DSSC using a low molecular gelator and the ILC electrolyte.

Main Results:

• The C(12)MImI/I(2) ILC electrolyte demonstrated higher short-circuit current density (J(SC)) and light-to-electricity conversion efficiency than non-liquid crystalline electrolytes.
• Higher conductivity of the ILC was attributed to enhanced exchange reactions between iodide species and formation of 2D conductive pathways.
• Addition of a gelator to the ILC improved DSSC efficiency by further enhancing conductivity and J(SC).

Conclusions:

• Ionic liquid crystals with a smectic A phase offer superior performance as DSSC electrolytes due to enhanced conductivity and charge transport.
• The 2D structure of the conductive pathway in ILCs plays a significant role in improving charge mobility.
• Quasi-solid-state DSSCs fabricated with gelator-modified ILC electrolytes show promising potential for efficient energy conversion.