Robust nonfullerene solar cells approaching unity external quantum efficiency enabled by suppression of geminate recombination

Derya Baran, Nicola Gasparini, Andrew Wadsworth, Ching Hong Tan, Nimer Wehbe, Xin Song, Zeinab Hamid, Weimin Zhang, Marios Neophytou, Thomas Kirchartz, Christoph J. Brabec, James R. Durrant, Iain McCulloch

Research output: Contribution to journalArticlepeer-review

107 Scopus citations

Abstract

Nonfullerene solar cells have increased their efficiencies up to 13%, yet quantum efficiencies are still limited to 80%. Here we report efficient nonfullerene solar cells with quantum efficiencies approaching unity. This is achieved with overlapping absorption bands of donor and acceptor that increases the photon absorption strength in the range from about 570 to 700 nm, thus, almost all incident photons are absorbed in the active layer. The charges generated are found to dissociate with negligible geminate recombination losses resulting in a short-circuit current density of 20 mA cm-2 along with open-circuit voltages >1 V, which is remarkable for a 1.6 eV bandgap system. Most importantly, the unique nano-morphology of the donor:acceptor blend results in a substantially improved stability under illumination. Understanding the efficient charge separation in nonfullerene acceptors can pave the way to robust and recombination-free organic solar cells.
Original languageEnglish (US)
JournalNature Communications
Volume9
Issue number1
DOIs
StatePublished - May 25 2018

Fingerprint Dive into the research topics of 'Robust nonfullerene solar cells approaching unity external quantum efficiency enabled by suppression of geminate recombination'. Together they form a unique fingerprint.

Cite this