Accurate Determination of Hole Transport Energy Offset in Non-Fullerene Organic Solar Cells
발표자
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초록
내용
In non-fullerene organic photovoltaic cells, a hole transfer state (hECT) from the acceptor to the donor has a great influence on the device performance. However, the method for determining the accurate hECT still remains an open challenge. Here, we suggest a simple method to determine the accurate hECT by deconvolution of electroluminescence spectrum of blend (ELB). Under the conditions that (i) absorption of the donor and acceptor are separated sufficiently, and (ii) the onset part of the external quantum efficiency (EQE) is formed solely by the contribution of the acceptor only, ELB can be deconvoluted into the contribution of the singlet recombination of the acceptor and the radiative recombination via hECT. Through the deconvolution of ELB, we have clearly decided which part of the broad ELB spectrum should be used to apply the Marcus theory.