High-Performance Near-Infrared Absorbing n-Type Porphyrin Acceptor for Organic Solar Cells

다국어 초록 (Multilingual Abstract)

<P>While the outstanding charge transport and sunlight-harvesting properties of porphyrin molecules are highly attractive as active materials for organic photovoltaic (OPV) devices, the development of n-type porphyrin-based electron acceptors has been challenging. In this work, we developed a high-performance porphyrin-based electron acceptor for OPVs by substitution of four naphthalene diimide (NDI) units at the perimeter of a Zn-porphyrin (P<SUB>Zn</SUB>) core using ethyne linkage. Effective π-conjugation between four NDI wings and the <I>P</I><SUB>Zn</SUB> core significantly broadened Q-band absorption to the near infrared region, thereby achieving the narrow band gap of 1.33 eV. Employing a windmill-structured tetra-NDI substituted <I>P</I><SUB>Zn</SUB>-based acceptor (<I>P</I><SUB>Zn</SUB>-TNDI) and mid-band gap polymer donor (PTB7-Th), the bulk heterojunction OPV devices achieved a power conversion efficiency (PCE) of 8.15% with an energy loss of 0.61 eV. The PCE of our <I>P</I><SUB>Zn</SUB>-TNDI-based device was the highest among the reported OPVs using porphyrin-based acceptors. Notably, the amorphous characteristic of <I>P</I><SUB>Zn</SUB>-TNDI enabled optimization of the device performance without using any additive, which should make industrial fabrication simpler and cheaper.</P>
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