Polymer-Entangled Spontaneous Pseudo-Planar Heterojunction for Constructing Efficient Flexible Organic Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Organic Electronics

Background:

• Flexible organic solar cells (FOSCs) are promising for portable power but face challenges in power conversion efficiency (PCE), stretchability, and mechanical stability.
• Existing bulk heterojunction (BHJ) films have limitations in tensile properties and energy conversion.

Purpose of the Study:

• To synergistically optimize PCE and mechanical properties of FOSCs.
• To develop a novel film morphology for enhanced performance and durability.

Main Methods:

• Green sequential printing combined with polymer-induced spontaneous gradient heterojunction phase separation morphology.
• Fabrication of toughened-pseudo-planar heterojunction (Toughened-PPHJ) films.
• Finite element simulation for stress distribution analysis.

Main Results:

• The Toughened-PPHJ film demonstrated a crack onset strain (COS) of 11.0%, double that of the reference BHJ film (5.5%).
• The optimal device achieved a high PCE of 18.16%, with enhanced short-circuit current density (J_SC) and reduced energy loss compared to BHJ devices (16.99%).
• The 1 cm² flexible Toughened-PPHJ device retained over 92% of its initial PCE after 1000 bending cycles.

Conclusions:

• The proposed entangled strategy and Toughened-PPHJ morphology effectively enhance both the power conversion efficiency and mechanical robustness of FOSCs.
• This approach offers a viable strategy for developing advanced flexible portable power supplies for wearable electronics.