Intrinsically Stretchable, Highly Efficient Organic Solar Cells Enabled by Polymer Donors Featuring Hydrogen-Bonding...

Area of Science:

• Materials Science
• Organic Electronics
• Renewable Energy

Background:

• Intrinsically stretchable organic solar cells (IS-OSCs) are crucial for wearable electronics.
• Current efficient organic solar cells (OSCs) often use brittle active layers, limiting their application in flexible devices.
• Developing stretchable active layers that maintain high performance is a key challenge.

Purpose of the Study:

• To design and synthesize novel polymer donors (PhAmX) with integrated flexible spacers for intrinsically stretchable organic solar cells.
• To investigate the impact of phenyl amide (PhAm)-based flexible spacers on the molecular ordering, mechanical properties, and photovoltaic performance of OSCs.
• To achieve high power conversion efficiency (PCE) and excellent stretchability in IS-OSCs.

Main Methods:

• Synthesis of new polymer donors (PhAmX) incorporating phenyl amide (PhAm)-based flexible spacers (FS).
• Fabrication and characterization of intrinsically stretchable organic solar cells (IS-OSCs) using the developed polymer donors.
• Evaluation of photovoltaic performance (PCE) and mechanical stretchability (PCE retention under strain) of the fabricated devices.
• Comparative study of PhAm:Y7 blends in both rigid and stretchable OSCs against reference materials (PM6:Y7).

Main Results:

• The developed PhAmX polymer donors enabled IS-OSCs with a high PCE of 12.73% and retained over 80% of their initial PCE at 32% strain.
• The phenyl amide (PhAm)-based flexible spacer (FS) enhanced molecular ordering and interactions with the Y7 acceptor, improving both mechanical stretchability and electrical properties.
• In rigid OSCs, the PhAm5:Y7 blend demonstrated a significantly higher PCE (17.5%) compared to the reference PM6:Y7 blend.
• The study provides a thorough investigation into the structure-property relationships of the PhAm-FS linker in OSCs.

Conclusions:

• The incorporation of phenyl amide (PhAm)-based flexible spacers into polymer donors is an effective strategy for simultaneously enhancing the mechanical stretchability and photovoltaic performance of organic solar cells.
• The developed PhAmX-based IS-OSCs represent a significant advancement, offering superior performance compared to previously reported stretchable OSCs.
• This work opens new avenues for the design of high-performance, mechanically robust organic electronic devices for next-generation wearable applications.