Molecularly Interlocked Interfaces Enable Record-Efficiency Stretchable Organic Photovoltaics.

Abstract

The development of stretchable organic solar cells (s-OSCs) demands concurrent breakthroughs in mechanical compliance and electronic properties, and the challenge is rooted in the intrinsic mechanical mismatch between organic semiconductors and metal electrodes. Here, this study proposes dual-phase interface engineering strategies to reconcile these conflicting requirements through molecularly interlocked conductive elastomers. Dynamic stress dissipation through dynamic bond plasticity is achieved by embedding a 3D interpenetrating conducting elastomer network within the electron transport layer (ETL). The strategy creates gradient modulus interfaces through Ag coordination-enabled nanocomposite bonding, suppressing crack propagation velocities and reduces the interfacial mechanical mismatch phenomenon. Eventually, the PCE of 19.58% is achieved on the small-area flexible devices, which is one of the highest PCEs for flexible organic solar cells (f-OSCs) to date. Notably, the stretchable devices retain over the PCE of 10% under 100% tensile strain, surpassing previous stretchable photovoltaic devices. To further validate the potential of this strategy for large-area module applications, 25 cm²-based flexible and stretchable modules are prepared with PCEs of 16.74% and 14.48%, respectively. The work redefines material design rules for deformable electronics by establishing a generic mechanically adaptive framework that synchronizes interfacial dynamics across molecular to macroscopic scales.