Achieving Record‐High Stretchability and Mechanical Stability in Organic Photovoltaic Blends with a Dilute‐absorber Strategy

• Published in: Advanced materials (Weinheim) 2024-02, Vol.36 (8), p.e2307278-n/a
• Main Authors: Li, Saimeng, Gao, Mengyuan, Zhou, Kangkang, Li, Xin, Xian, Kaihu, Zhao, Wenchao, Chen, Yu, He, Chunyong, Ye, Long
• Format: Article
• Language: English
• Subjects: Absorbers; Dilution; Elastic recovery; Elastomers; Energy conversion efficiency; film stretchability; mechanical stability; organic solar cells; Performance measurement; Photovoltaic cells; Polymer blends; polymer elastomer; Polymers; Solar cells; Stability; Strain; Stretchability; stretchable solar cells; Tensile properties; Tensile tests; Wearable technology
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202307278

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, this work proposes a facile and low‐cost strategy for constructing intrinsically stretchable OSCs by introducing a readily accessible polymer elastomer as a diluent for all‐polymer 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 are realized in the OSCs active layers for the first time. Specifically, the tensile properties of best‐performing all‐polymer photovoltaic blends are increased by up to 250 times after blending. Previously unattainable performance metrics (fracture strain >50% and PCE >10%) are achieved simultaneously for the resulting photovoltaic films. Furthermore, an overall evaluation parameter y is proposed for the efficiency‐cost‐ stretchability balance of photovoltaic blend films. The y value of dilute‐absorber system is two orders of magnitude greater than those of prior state‐of‐the‐art systems. Additionally, intrinsically stretchable devices are prepared to showcase the mechanical stability. Overall, this work offers a new avenue for constructing and comprehensively evaluating intrinsically stretchable organic electronic films. Intrinsically stretchable organic photovoltaic active layers are constructed by introducing a readily available polymer elastomer to best‐performance photovoltaic polymers. Record‐high stretchability with fracture strain up to 1000% and elastic recovery over 90% under cyclic tensile tests are realized for the first time. Specifically, previously unattainable performance metrics (fracture strain >50%, photovoltaic efficiency>10%) are simultaneously achieved in the resulting photovoltaic films.