Organic Photovoltaics: The Impact of Non-fullerene Acceptors
With the emergence of non-fullerene acceptors five years ago, the power conversion efficiency of organic solar cells (OSCs) has increased remarkably, from some 12% to over 18%. In OSCs, the active layers consist of bulk-heterojunctions, that is blends of an electron acceptor and an electron donor component. The inter-molecular charge transfer electronic states that appear at the donor-acceptor interfaces play a crucial role in the exciton-dissociation, charge-separation, and charge-recombination processes .
In this presentation, we will discuss how the combination of state-of-the-art electronic structure calculations and molecular dynamics simulations allows a reliable description of (i) the molecular packing at the donoracceptor interfaces; (ii) the nature and energetic distribution of the charge-transfer electronic states; and (iii) the rates of radiative and nonradiative charge recombinations. In all, the results provide a molecular understanding of the factors that contribute to high efficiency [2-4] and pave the way towards reaching the Shockley-Queisser limit.
This work is funded by the Office of Naval Research.
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