Recently, a new type of active layer with a ternary system has been developed to further enhance the performance of binary system organic photovoltaics (OPV). In the ternary OPV, almost all active layers are formed by simple ternary blend in solution, which eventually leads to the disordered bulk heterojunction (BHJ) structure after a spin‐coating process. There are two main restrictions in this disordered BHJ structure to obtain higher performance OPV. One is the isolated second donor or acceptor domains. The other is the invalid metal–semiconductor contact. Herein, the concept and design of donor/acceptor/acceptor ternary OPV with more controlled structure (C‐ternary) is reported. The C‐ternary OPV is fabricated by a sequential solution process, in which the second acceptor and donor/acceptor binary blend are sequentially spin‐coated. After the device optimization, the power conversion efficiencies (PCEs) of all OPV with C‐ternary are enhanced by 14–21% relative to those with the simple ternary blend; the best PCEs are 10.7 and 11.0% for fullerene‐based and fullerene‐free solar cells, respectively. Moreover, the averaged PCE value of 10.4% for fullerene‐free solar cell measured in this study is in great agreement with the certified one of 10.32% obtained from Newport Corporation.
Herein, we report the first example of a crystalline metal–donor–fullerene framework, in which control of the donor–fullerene mutual orientation was achieved through chemical bond formation, in particular, by metal coordination. The13C cross‐polarization magic‐angle spinning NMR spectroscopy, X‐ray diffraction, and time‐resolved fluorescence spectroscopy were performed for comprehensive structural analysis and energy‐transfer (ET) studies of the fulleretic donor–acceptor scaffold. Furthermore, in combination with photoluminescence measurements, the theoretical calculations of the spectral overlap function, Förster radius, excitation energies, and band structure were employed to elucidate the photophysical and ET processes in the prepared fulleretic material. We envision that the well‐defined fulleretic donor–acceptor materials could contribute not only to the basic science of fullerene chemistry but would also be used towards effective development of organic photovoltaics and molecular electronics.
more » « less- PAR ID:
- 10017863
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie
- Volume:
- 128
- Issue:
- 31
- ISSN:
- 0044-8249
- Page Range / eLocation ID:
- p. 9216-9220
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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