Fast charge separation in a non-fullerene organic solar cell with a small driving force
2016 (English)In: NATURE ENERGY, ISSN 2058-7546, Vol. 1, 16089Article in journal (Refereed) Published
Fast and efficient charge separation is essential to achieve high power conversion efficiency in organic solar cells (OSCs). In state-of-the-art OSCs, this is usually achieved by a significant driving force, defined as the offset between the bandgap (E-gap) of the donor/acceptor materials and the energy of the charge transfer (CT) state (E-CT), which is typically greater than 0.3 eV. The large driving force causes a relatively large voltage loss that hinders performance. Here, we report non-fullerene OSCs that exhibit ultrafast and efficient charge separation despite a negligible driving force, as E-CT is nearly identical to E-gap. Moreover, the small driving force is found to have minimal detrimental effects on charge transfer dynamics of the OSCs. We demonstrate a non-fullerene OSC with 9.5% efficiency and nearly 90% internal quantum efficiency despite a low voltage loss of 0.61V. This creates a path towards highly efficient OSCs with a low voltage loss.
Place, publisher, year, edition, pages
NATURE PUBLISHING GROUP , 2016. Vol. 1, 16089
Other Physics Topics
IdentifiersURN: urn:nbn:se:liu:diva-135409DOI: 10.1038/NENERGY.2016.89ISI: 000394175200001OAI: oai:DiVA.org:liu-135409DiVA: diva2:1081476
Funding Agencies|National Basic Research Program of China (973 Program) [2013CB834701, 2014CB643501]; Hong Kong Research Grants Council [T23-407/13 N, N_HKUST623/13, 606012]; HK JEBN Limited; National Science Foundation of China [21374090, 51361165301]; Office of Naval Research [N000141410531, N000141512322, N000141310526 P00002]; Office of Science, Office of Basic Energy Sciences, of the US Department of Energy [DE-AC02-05CH11231]; Swedish Research Council (VR) [330-2014-6433]; Swedish Research Council (FORMAS) [942-2015-1253]; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (faculty grant SFO-Mat-LiU) [2009-00971]; European Commission [691210, INCA 600398]; Wallenberg Scholar grant2017-03-142017-03-142017-03-14