Efficient and Stable Air-Processed Ternary Organic Solar Cells Incorporating Gallium-Porphyrin as an Electron Cascade...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) rely on efficient charge transfer between donor and acceptor materials.
• Ternary blends offer potential for improved performance through cascade energy level alignment.
• Gallium porphyrins are explored as novel components in organic electronic devices.

Purpose of the Study:

• To synthesize and evaluate two gallium porphyrins, (TPP)GaCl and (OEP)GaCl, as electron cascade materials in ternary OSCs.
• To investigate the effect of porphyrin concentration on the performance and morphology of organic bulk heterojunction films.
• To assess the impact of these porphyrins on device efficiency, charge dynamics, and photostability.

Main Methods:

• Synthesis of tetraphenyl GaCl porphyrin ((TPP)GaCl) and octaethylporphyrin GaCl porphyrin ((OEP)GaCl).
• Fabrication of ternary OSCs incorporating gallium porphyrins with P3HT or PCDTBT donors and PCBM acceptors.
• Characterization of film morphology using X-ray diffraction (XRD) and atomic force microscopy (AFM).
• Performance evaluation of OSCs, including power conversion efficiency (PCE) and photostability testing.

Main Results:

• Gallium porphyrins demonstrated energy level matching for efficient electron cascade with polymer donors and PCBM.
• Ternary OSCs with low concentrations of (TPP)GaCl showed a ~17% increase in PCE due to enhanced exciton dissociation and electron transport.
• High concentrations of gallium porphyrins led to rough nanomorphology, suppressed crystallinity, and reduced device efficiency.
• Optimized ternary devices exhibited improved photostability compared to binary devices.

Conclusions:

• Gallium porphyrins can serve as effective electron cascade materials in ternary OSCs.
• Careful control of porphyrin concentration is crucial for optimizing film morphology and device performance.
• (TPP)GaCl at low concentrations offers a promising strategy for enhancing both efficiency and stability in organic solar cells.