High-Performance Intrinsically Stretchable Polymer Solar Cell with Record Efficiency and Stretchability Enabled by Thymine-Functionalized Terpolymer
Qingpei Wan, Soodeok Seo, Sunwoo Lee, Jinho Lee, Hyesu Jeon, Taek‐Soo Kim, Bumjoon J. Kim, Barry C. Thompson
Abstract
Designing new polymer semiconductors for intrinsically stretchable polymer solar cells (IS-PSCs) with high power conversion efficiency (PCE) and durability is critical for wearable electronics applications. Nearly all high-performance PSCs are constructed using fully conjugated polymer donors ( P D ) and small-molecule acceptors (SMA). However, a successful molecular design of P D s for high-performance and mechanically durable IS-PSCs without sacrificing conjugation has not been realized. In this study, we design a novel thymine side chain terminated 6,7-difluoro-quinoxaline (Q-Thy) monomer and synthesize a series of fully conjugated P D s (PM7-Thy5, PM7-Thy10, PM7-Thy20) featuring Q-Thy. The Q-Thy units capable of inducing dimerizable hydrogen bonding enable strong intermolecular P D assembly and highly efficient and mechanically robust PSCs. The PM7-Thy10:SMA blend demonstrates a combination of high PCE (>17%) in rigid devices and excellent stretchability (crack-onset value >13.5%). More importantly, PM7-Thy10-based IS-PSCs show an unprecedented combination of PCE (13.7%) and ultrahigh mechanical durability (maintaining 80% of initial PCE after 43% strain), illustrating the promising potential for commercialization in wearable applications.