Ultra-flexible organic photovoltaics (OPVs) are promising candidates for next-generation power sources owing to their low weight, transparency, and flexibility. However, obtaining ultra-flexibility under extreme repetitive mechanical stress while maintaining optical transparency remains challenging because of the intrinsic brittleness of transparent electrodes. Here, we introduce strain-durable ultra-flexible semitransparent OPVs with a thickness below 2 μm. The conformal surface coverage of nanoscale thin metal electrodes (< 10 nm) is achieved, resulting in extremely low flexural rigidity and high strain durability. In-depth optical and electrical analyses on ultrathin metal electrodes showed that the devices maintain over 73% of their initial efficiency after 1000 cycles of repetitive compression and release at 66% compressive strain, and the average visible light transmittances remain higher than 30%. To our knowledge, this is the first systematical study on mechanical behaviors of strain-durable ultra-flexible ST-OPVs through precise adjustment of each ultrathin electrode thickness toward the emergence of next-generation flexible power sources.
This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. RS-2023-00213089). This work was supported by the Technology Innovation Program (Grant No. RS-2022-00154781, Development of large-area wafer-level flexible/stretchable hybrid sensor platform technology for form factor-free highly integrated convergence sensor) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea). This research was also supported by the MSIT, Korea, under the ITRC (Information Technology Research Center) support program (Grant No. IITP-2023-2020-0-01461) supervised by the IITP (Institute for Information & communications Technology Planning & Evaluation). This study was supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (NRF-2021K1A4A7A03093851).
