title: Deep absorbing porphyrin small molecule for high-performance organic solar cells with very low energy losses.
abstract: We designed and synthesized the DPPEZnP-TEH molecule, with a porphyrin ring linked to two diketopyrrolopyrrole units by ethynylene bridges. The resulting material exhibits a very low energy band gap of 1.37 eV and a broad light absorption to 907 nm. An open-circuit voltage of 0.78 V was obtained in bulk heterojunction (BHJ) organic solar cells, showing a low energy loss of only 0.59 eV, which is the first report that small molecule solar cells show energy losses <0.6 eV. The optimized solar cells show remarkable external quantum efficiency, short circuit current, and power conversion efficiency up to 65%, 16.76 mA/cm(2), and 8.08%, respectively, which are the best values for BHJ solar cells with very low energy losses. Additionally, the morphology of DPPEZnP-TEH neat and blend films with PC61BM was studied thoroughly by grazing incidence X-ray diffraction, resonant soft X-ray scattering, and transmission electron microscopy under different fabrication conditions.
authors.affiliation: †State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, P. R. China.
authors.forename: Ke
authors.initials: K
authors.lastname: Gao
authors.affiliation: †State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, P. R. China.
authors.forename: Lisheng
authors.initials: L
authors.lastname: Li
authors.affiliation: †State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, P. R. China.
authors.forename: Tianqi
authors.initials: T
authors.lastname: Lai
authors.affiliation: †State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, P. R. China.
authors.forename: Liangang
authors.initials: L
authors.lastname: Xiao
authors.affiliation: †State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, P. R. China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Huang
authors.affiliation: †State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, P. R. China.
authors.forename: Fei
authors.initials: F
authors.lastname: Huang
authors.affiliation: †State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, P. R. China.
authors.forename: Junbiao
authors.initials: J
authors.lastname: Peng
authors.affiliation: †State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, P. R. China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Cao
authors.affiliation: ‡Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: ‡Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.|¶Polymer Science and Engineering Department, University of Massachusetts, Amherst, Massachusetts 01003, United States.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Russell
authors.affiliation: §Molecular Materials and Nanosystems, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: René A J
authors.initials: RA
authors.lastname: Janssen
authors.affiliation: †State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, 381 Wushan Road, Guangzhou, 510640, P. R. China.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Peng