Long-term stable polymer solar cells with significantly reduced burn-in loss

• Published in: Nature communications 2014-12, Vol.5 (1), p.5688-5688, Article 5688
• Main Authors: Kong, Jaemin, Song, Suhee, Yoo, Minji, Lee, Ga Young, Kwon, Obum, Park, Jin Kuen, Back, Hyungcheol, Kim, Geunjin, Lee, Seoung Ho, Suh, Hongsuk, Lee, Kwanghee
• Format: Article
• Language: English
• Subjects: 639/301/119; 639/301/299/946; 639/624/1075/524; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms6688

The inferior long-term stability of polymer-based solar cells needs to be overcome for their commercialization to be viable. In particular, an abrupt decrease in performance during initial device operation, the so-called ‘burn-in’ loss, has been a major contributor to the short lifetime of polymer solar cells, fundamentally impeding polymer-based photovoltaic technology. In this study, we demonstrate polymer solar cells with significantly improved lifetime, in which an initial burn-in loss is substantially reduced. By isolating trap-embedded components from pristine photoactive polymers based on the unimodality of molecular weight distributions, we are able to selectively extract a trap-free, high-molecular-weight component. The resulting polymer component exhibits enhanced power conversion efficiency and long-term stability without abrupt initial burn-in degradation. Our discovery suggests a promising possibility for commercial viability of polymer-based photovoltaics towards real solar cell applications. Efficiency and stability are two major concerns in polymer-based solar cell development. Here Kong et al. report that the lifetime of a bulk heterojunction polymer can be improved by removing its low-molecular-weight components, which leads to a substantially reduced burn-in loss under photo-aging conditions.