Redox Shuttle-Based Electrolytes for Dye-Sensitized Solar Cells: Comprehensive Guidance, Recent Progress, and Future...

Area of Science:

• Materials Science
• Electrochemistry
• Renewable Energy

Background:

• Redox electrolytes are vital for dye-sensitized solar cells (DSSCs), influencing photovoltage and photocurrent.
• The traditional iodide/triiodide (I^-/I₃^-) redox shuttle limits open-circuit voltage (V_oc) to 0.7-0.8 V.
• Cobalt and copper complexes have shown promise, achieving V_oc > 1 V and power conversion efficiencies (PCE) up to 15%.

Purpose of the Study:

• To develop alternative redox shuttles for DSSCs with higher redox potentials.
• To enable the use of highly efficient porphyrin and organic dyes with DSSCs.
• To enhance the overall power conversion efficiency (PCE) and performance of DSSCs.

Main Methods:

• Investigated cobalt and copper complex-based redox shuttles.
• Explored alternative redox shuttles with redox potentials of 0.45-0.65 V.
• Developed a strategy involving superior counter electrodes and near-infrared (NIR)-absorbing dyes for cosensitization.

Main Results:

• Achieved PCE > 14% with cobalt complexes and V_oc up to 1 V.
• Reported PCE > 15% with copper-complex-based redox shuttles, with potential for indoor applications (PCE > 34% under ambient light).
• Proposed a strategy yielding PCE > 16% by enhancing the fill factor and broadening light absorption.

Conclusions:

• Advanced redox shuttles are crucial for overcoming the limitations of traditional I^-/I₃^- systems in DSSCs.
• Copper-complex-based redox shuttles show significant potential for both 1-sun and indoor light applications.
• A combination of optimized redox shuttles, counter electrodes, and dyes is key to achieving higher PCE in DSSCs.