AbstractSpectroscopic measurements of charge transfer (CT) states provide valuable insight into the voltage losses in organic photovoltaics (OPVs). Correct interpretation of CT-state spectra depends on knowledge of the underlying broadening mechanisms, and the relative importance of molecular vibrational broadening and variations in the CT-state energy (static disorder). Here, we present a physical model, that obeys the principle of detailed balance between photon absorption and emission, of the impact of CT-state static disorder on voltage losses in OPVs. We demonstrate that neglect of CT-state disorder in the analysis of spectra may lead to incorrect estimation of voltage losses in OPV devices. We show, using measurements of polymer:non-fullerene blends of different composition, how our model can be used to infer variations in CT-state energy distribution that result from variations in film microstructure. This work highlights the potential impact of static disorder on the characteristics of disordered organic blend devices.
Bibliographical noteKAUST Repository Item: Exported on 2021-06-21
Acknowledgements: J.N., J.Y., E.R., M.A. and F.D.E. thank the European Research Council for support under the European Union’s Horizon 2020 research and innovation program (Grant Agreement No. 742708). E.R. is grateful to the Fonds de Recherche du Quebec-Nature et technologies (FRQNT) for a postdoctoral fellowship and acknowledges financial support from the European Cooperation in Science and Technology. M.A. thanks the Engineering and Physical Sciences Research Council (EPSRC) for support via doctoral studentships. F.E. thanks the Engineering and Physical Sciences Research Council (EPSRC) for support via the Post-Doctoral Prize Fellowship. We thank Dr. Andrew Wadsworth from Department of Chemistry at Imperial College London and Prof. Iain McCulloch from KAUST Solar Center (KSC) at King Abdullah University of Science and Technology, for providing materials O-IDTBR and O-IDTBR, and extra support of O-IDFBR by Joel Luke from Department of Physics at Imperial College London. J.Y. thank Beverly Ge for her support.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology
- General Chemistry
- General Physics and Astronomy