Evidences of photocurrent generation by hole–exciton interaction at organic semiconductor interfaces

• Published in: Organic electronics Vol. 26; pp. 75 - 80
• Main Authors: Li, Ping, Zhang, Yu Jun, Cai, Lun, Ding, Bao Fu, Xiang, Jin, Wang, Gang, Alameh, Kamal, Zhou, Da Chen, Song, Qun Liang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2015
• Subjects: Exciton dissociation; Hole–exciton interaction; Organic semiconductor interfaces; Organic solar cells; Exciton dissociation; Organic solar cells; Organic semiconductor interfaces; Hole–exciton interaction
• ISSN: 1566-1199; 1878-5530
• DOI: 10.1016/j.orgel.2015.07.024

[Display omitted] •Photocurrent contribution from hole–exciton interaction was confirmed.•The jump of EQE around 800nm after adding a bias light shows a direct evidence.•The superlinear dependence of photocurrent on light intensity provides evidence.•The EQE variations under bias light of various wavelengths provide further evidence. The charge–exciton interaction at the donor/acceptor interface plays a significant role in the exciton dissociation processes, and thus influences the performance of organic solar cells. In this work, the evidences of photocurrent generation via hole–exciton interaction (HEI) at the organic semiconductor interface in organic solar cells, which is the counterpart of photocurrent generated by electron–exciton interaction, is demonstrated. A heterojunction, composed of copper phthalocyanine (CuPc) and fullerene (C60), is used to provide free holes that interact with the excitons supplied by perfluorinated hexadecafluorophthalo-cyaninatozinc (F16ZnPc). The fact that photocurrent generation via HEI is well evidenced by: (1) a short circuit current of 0.38mAcm−2; (2) the jump of an external quantum efficiency (EQE) around 800nm after adding a bias light; (3) the EQE variations under bias light of different wavelengths and light intensities; and (4) the superlinear dependence of the photocurrent on the light intensity.