Light-Induced Interfacial Dynamics Dramatically Improve the Photocurrent in Dye-Sensitized Solar Cells: An...

Area of Science:

• Materials Science
• Photovoltaics
• Electrochemistry

Background:

• Triphenylamine-based D-π-A organic dyes are utilized in dye-sensitized solar cells (DSSCs).
• Cobalt bipyridine redox complexes serve as electrolytes in DSSCs.
• Light soaking can induce changes in solar cell performance.

Purpose of the Study:

• Investigate the significant increase in photocurrent generation during light soaking in DSSCs.
• Identify the role of the electrolyte in performance improvement.
• Understand the underlying mechanisms of enhanced charge transfer and collection efficiency.

Main Methods:

• Fabrication and testing of DSSCs sensitized with PD2 and LEG1 dyes.
• Electrolyte manipulation and pre-treatment experiments.
• Interfacial charge-transfer kinetics studies.
• Photoelectron spectroscopic measurements (PES).

Main Results:

• A significant increase in photocurrent and incident photon-to-current efficiency (IPCE) was observed after light soaking.
• The electrolyte, specifically tetrabutylammonium perchlorate (TBAP), was identified as crucial for performance enhancement.
• Interfacial charge-transfer studies revealed a slow injection component, leading to increased electron lifetime and collection efficiency.
• PES indicated energy shifts at the dye/TiO2 interface, suggesting electrolyte-induced dye reorganization.

Conclusions:

• The electrolyte plays a critical role in the performance enhancement of organic solar cells sensitized with triphenylamine dyes.
• Electrolyte-induced dye reorganization at the dye/TiO2 interface is a key factor contributing to improved photocurrent generation and device efficiency.
• Understanding these interfacial dynamics is essential for optimizing organic solar cell design and performance.