Strain-induced power output enhancement in intrinsically stretchable organic solar cells

Intrinsically stretchable organic solar cells (IS-OSCs) are a promising class of wearable power sources. Although the power conversion efficiency (PCE) and mechanical stretchability of IS-OSCs have significantly improved, the current stretchability level still falls short of meeting the demands of wearable electronics. The power output (PCE x photoactive area) of these OSCs is a key figure of merit in determining their potential as power sources. However, the impact of stretching on changes in the photoactive area and the resulting power output has not been investigated. In this study, we construct highly stretchable and efficient photoactive systems by designing a polymer donor, PBET-TF. IS-OSCs based on PBET-TF maintain over 80% of their original PCE up to 50% strain (strain at PCE80% = 50%), which significantly outperforms the reference PBDB-TF-based IS-OSCs (strain at PCE80% = 11%). Importantly, for the first time, we demonstrate strain- induced power output increases in IS-OSCs using the developed PBET-TF-based photoactive systems.