Precise Control Over Crystallization Kinetics by Combining Nucleating Agents and Plasticizers for 20.1% Efficiency...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Controllable active layer morphology is crucial for enhancing organic solar cell (OSC) performance.
• Existing strategies often struggle with precise control over morphology evolution.
• Developing advanced morphology control methods is key to achieving higher power conversion efficiencies.

Purpose of the Study:

• To employ a quaternary strategy for precise modulation of crystallization kinetics and active layer morphology in OSCs.
• To investigate the synergistic effects of polymer donor D18-Cl and small molecule acceptor AITC on morphology.
• To achieve optimized 3D morphology for improved device performance and reduced energy loss.

Main Methods:

• Incorporation of polymer donor D18-Cl and small molecule acceptor AITC into a host D18:N3 system.
• In situ spectroscopic measurements during film formation to monitor crystallization kinetics and morphology evolution.
• Analysis of the effects of dual-guests on donor/acceptor aggregation and intermixing.

Main Results:

• D18-Cl acted as a nucleator, promoting D18 aggregation and donor/acceptor intermixing.
• AITC acted as a plasticizer, opposing N3 aggregation and intermixing kinetics.
• The combined effect resulted in synergistic control over fibrillar networks, multi-length scale morphology, and vertical phase distribution, leading to an optimized 3D morphology.

Conclusions:

• The quaternary strategy enables synergistic control over active layer morphology through mutually compensational effects of dual-guests.
• Optimized morphology enhances exciton dissociation, charge transfer, suppresses recombination, and reduces energy loss.
• Achieved a power conversion efficiency of 20.1% for single-junction OSCs, demonstrating an effective approach for high-performance devices.