Solution-processable nickel oxide hole transport layer for polymer donor with deep HOMO level
발표자
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초록
내용
Maximizing the charge transport between the polymer active layer and the charge transport layer is crucial for achieving high performance in organic solar cells (OSCs). In this work, energy level matching between the HOMO of the donor polymer and the work function (WF) of the hole transport layer is investigated. Particularly, since NiO has a low WF value (5.1 eV), the efficiency of NiO-OSCs based on donor polymer PBDB-T-2F (HOMO 5.6 eV) and non-fullerene acceptor Y6 is somewhat suppressed. To resolve this problem, a dipole layer based on the 4-(trifluoromethyl)benzoic acid (PTF-BOA) is used to modify the work function of NiO layer (NiO-PTF-BOA). The carboxyl group of PTF-BOA is bonded with Ni atoms on the NiO surface, while the CF3 group attracts electrons, thus resulting in a partial negative charge on the CF3 side. This PTF-BOA dipole layer induces the vacuum level up shift thus enhancing the work function of NiO-PTF-BOA to 5.5 eV. The PBDB-T-2F:Y6 OSCs with NiO-PTF-BOA exhibit an efficiency of 16.36%, which is the highest reported efficiency for NiO-based OSCs.