20.500.12556/RUNG-4981-a9e58771-193f-4ad9-7e2c-a3b86e7564d5
Elucidation of Donor:Acceptor Phase Separation in Nonfullerene Organic Solar Cells and Its Implications on Device Performance and Charge Carrier Mobility
In bulk-heterojunction solar cells, the device performance strongly depends on the donor and acceptor properties, the phase separation in the absorber layer, and the formation of a bicontinuous network. While this phase separation is well explored for polymer:fullerene solar cells, only little is known for polymer:nonfullerene acceptor solar cells. The main hurdle in this regard is often the chemical similarity of the conjugated polymer donor and the organic nonfullerene acceptor (NFA), which makes the analysis of the phase separation via atomic force microscopic (AFM) phase images or conventional transmission electron microscopy difficult. In this work, we use the donor polymer PTB7-Th and the small molecule acceptor O-IDTBR as the model system and visualized the phase separation in PTB7-Th:O-IDTBR bulk-heterojunctions with different donor:acceptor ratios via scanning transmission electron microscopy (STEM) high-angle annular dark-field (HAADF) images and electron energy loss spectroscopy (EELS) based elemental mapping, which resulted in a good contrast between the donor and the acceptor despite very low differences in the chemical composition. AFM as well as grazing-incidence wide-angle X-ray scattering (GIWAXS) investigations support the electron microscopic data. Furthermore, we elucidate the implications of the phase separation on the device performance as well as charge carrier mobilities in the bulk-heterojunction layers, and a high performance of the solar cells was found over a relatively broad range of polymer domain sizes. This can be related to the larger domain sizes of the acceptor phase with higher amounts of O-IDTBR in the blend, while the polymer donor phase still forms continuous pathways to the electrode, which keeps the hole mobility at a relatively constant level.
nanomorphology bulk-heterojunction scanning transmission electron microscopy organic photovoltaics charge carrier mobility
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Angleški jezik
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2020-01-15 20:55:17
2020-01-15 22:42:11
2023-06-09 03:35:51
0000-00-00 00:00:00
2019
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0
7535-7545
2
10
2019
0000-00-00
Zaloznikova
NiDoloceno
NiDoloceno
0000-00-00
0000-00-00
0000-00-00
5544443
10.1021/acsaem.9b01534
URN:SI:UNG:REP:FLCJGBQB
acsaem.9b01534.pdf
acsaem.9b01534.pdf
1
7AF7DC4056D8CD49E3510B54F6FF98C7
d06055cd83e8ea57009c880b5d490640312bf26d24d38b970036db9ca7beb924
6d22712a-05cf-11ee-9c48-5ef991fed68f
https://repozitorij.ung.si/Dokument.php?lang=slv&id=19089
Univerza v Novi Gorici
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