The addition of a third component to a donor:acceptor blend is a powerful tool to enhance the power conversion efficiency of organic solar cells. Featuring a similar operating mechanism, organic photodetectors are also expected to benefit from this approach. Here, we fabricated ternary organic photodetectors, based on a polymer donor and two nonfullerene acceptors, resulting in a low dark current of 0.42 nA cm-2 at -2 V and a broadband specific detectivity of 1012 Jones. We found that exciton recombination in the binary blend is reduced in ternary devices due to the formation of a pseudo-binary microstructure with mixed donor-acceptor phases. With this approach a wide range of intermediate open-circuit voltages is accessible, without sacrificing light-to-current conversion. This results in ternary OPD with improved R values in the NIR. Moreover, morphology analyses reveal that ternary OPD devices showed improved microstructure ordering and consequentially higher charge carrier mobilities compared to the reference devices.
|Original language||English (US)|
|Journal||Journal of Physics: Materials|
|State||Published - Jun 16 2021|
Bibliographical noteKAUST Repository Item: Exported on 2021-06-22
Acknowledged KAUST grant number(s): OSR-2018-CRG/CCF-3079, OSR-2018-CRG7-3749, OSR-2019-CRG8-4086
Acknowledgements: N.G. Acknowledges the Imperial College Research Fellowship Scheme. GIWAXS experiments were performed at BL11 NCD-SWEET beamline at ALBA Synchrotron (Spain) with the collaboration of Dr Eduardo Solano. The authors acknowledge financial support from KAUST, including Office of Sponsored Research (OSR) awards no. OSR-2018-CRG/CCF-3079, OSR-2019-CRG8-4086 and OSR-2018-CRG7-3749. We acknowledge funding from ERC Synergy Grant SC2 (610115), the European Union’s Horizon 2020 research and innovation programme under grant agreement n° 952911, project BOOSTER, and grant agreement n° 862474, project RoLA-FLEX, as
well as EPSRC Project EP/T026219/1.