Revealing the Strain-Induced Morphological, Mechanical, and Photovoltaic Evolution of Self-Encapsulated and Semitransparent Intrinsically Stretchable Organic Solar Cells

Superior mechanical properties of intrinsically stretchable organic solar cells (is-OSCs) are of great importance to ensure long-term operational reliability, especially considering their potential application in wearable electronics and electronic skins. Herein, we have systematically investigated the morphology and mechanical and photovoltaic performance evolution of polymer–small molecule (PBDB-T:PCBM) and all-polymer (PBDB-T:N2200) blend films under strains and fabricated semitransparent is-OSCs through a self-encapsulation process. Except for the conventional mechanical and morphological characterizations including the film-on-water tensile test method, optical microscopy imaging, and dichroic ratio of the blend films, we have observed the evident polymer chain alignment along with external strains from atomic force microscopy images, which has rarely been reported before. Furthermore, the self-encapsulated semitransparent is-OSCs (average visible transmittance (AVT) ∼ 45%) revealed robust mechanical properties, achieving 80% power conversion efficiency (PCE) retention under 34% strain. Finally, the performance degradation of is-OSCs under strain and the degradation mechanism have been systematically investigated.