Controlling Morphology and Improving Stability with High-Boiling-Point Additive for Efficient Organic Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Organic Electronics

Background:

• Organic solar cells (OSCs) are crucial for renewable energy, but their performance is limited by active layer nanomorphology.
• Controlling nanomorphology is key to optimizing donor-acceptor blend properties and device efficiency.

Purpose of the Study:

• To investigate the use of 1,2,4-trichlorobenzene (1,2,4-TCB) as a high-boiling-point additive in OSCs.
• To compare the effects of 1,2,4-TCB with the conventional additive 1,8-diiodooctane (DIO) on OSC performance and stability.
• To elucidate the nanomorphological changes induced by 1,2,4-TCB.

Main Methods:

• Grazing incidence wide-angle X-ray scattering (GIWAXS) to analyze molecular ordering.
• Contact angle measurements to assess donor-acceptor miscibility.
• Device fabrication and performance testing (power conversion efficiency, PCE).
• Photostability and storage stability testing.

Main Results:

• 1,2,4-TCB enhanced acceptor molecular ordering and donor-acceptor miscibility compared to DIO.
• OSCs with 1,2,4-TCB achieved a higher PCE (18.80%) than those with DIO (17.56%).
• Optimized bicontinuous interpenetrating network morphology was observed, improving exciton separation and charge transport.
• 1,2,4-TCB devices showed significantly improved photostability (T80 = 981 h) and storage stability (T80 = 2708 h).

Conclusions:

• High-boiling-point additives like 1,2,4-TCB are effective in optimizing OSC nanomorphology.
• 1,2,4-TCB offers a superior strategy for enhancing OSC efficiency and long-term stability.
• This research provides a viable approach for advancing the commercialization of organic solar cell technology.