Mechanically robust and stretchable organic solar cells plasticized by small-molecule acceptors.

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Wearable devices require flexible and efficient power sources.
• Organic solar cells (OSCs) offer potential for lightweight and adaptable energy harvesting.
• Integrating ductility into high-performance OSCs remains a challenge.

Purpose of the Study:

• To design and synthesize a small-molecule acceptor (SMA) for enhancing the mechanical compliance and performance of stretchable organic solar cells (s-OSCs).
• To investigate the structure-property relationships governing miscibility and stretchability in SMA-polymer blends for s-OSCs.

Main Methods:

• Synthesis of an organosilane-functionalized SMA (BTP-Si4).
• Fabrication of s-OSC blends using BTP-Si4 and a polymer donor (PNTB6-Cl).
• Characterization of power conversion efficiency (PCE), mechanical properties (ultimate strain), miscibility, and electron mobility.
• Deformation testing of fabricated s-OSCs.

Main Results:

• The BTP-Si4 SMA significantly enhanced the ductility of OSC blends, achieving an ultimate strain (εu) of >95%.
• Blends of BTP-Si4 and PNTB6-Cl demonstrated a power conversion efficiency (PCE) of >16%.
• Developed s-OSCs maintained >80% PCE retention under 80% strain, showcasing robust performance under deformation.

Conclusions:

• The developed SMA, BTP-Si4, is crucial for achieving highly ductile and efficient s-OSCs.
• Miscibility and molecular structure are key factors in designing stretchable photovoltaic blends.
• This work provides a roadmap for creating advanced, ductile photovoltaic power sources for emerging wearable applications.