Achieving Record-high Stretchability and Mechanical Stability in Organic Photovoltaic Blends with a Dilute-absorber Strategy.

Organic solar cells (OSCs) have potential for applications in wearable electronics. Except for high power conversion efficiency (PCE), excellent tensile properties and mechanical stability are required for achieving high-performance wearable OSCs, while the present metrics barely meet the stretchable requirements. Herein, we propose a facile and low-cost strategy for constructing intrinsically stretchable OSCs by introducing a readily accessible polymer elastomer as a diluent for organic photovoltaic blends. Remarkably, record-high stretchability with a fracture strain of up to 1000% and mechanical stability with elastic recovery>90% under cyclic tensile tests were realized in the OSCs active layers for the first time. Specifically, the tensile properties of best-performing all-polymer photovoltaic blends were increased by up to 250 times after blending. Previously unattainable performance metrics (fracture strain >50% and PCE >10%) were achieved simultaneously for the resulting photovoltaic films. Furthermore, an overall evaluation parameter y was proposed for the efficiency-cost-stretchability balance of photovoltaic blend films. The y value of our dilute-absorber system was two orders of magnitude greater than those of prior state-of-the-art systems. Additionally, intrinsically stretchable devices were prepared to verify the mechanical stability. Overall, this work offers a new avenue for constructing and comprehensively evaluating intrinsically stretchable organic electronic films. This article is protected by copyright. All rights reserved.