Impact of the Crystallite Orientation Distribution on Exciton Transport in Donor–Acceptor Conjugated Polymers

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• 作者：Alexander L. Ayzner ; Jianguo Mei ; Anthony Appleton ; Dean DeLongchamp ; Alexandre Nardes ; Stephanie Benight ; Nikos Kopidakis ; Michael F. Toney ; Zhenan Bao
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：December 30, 2015
• 年：2015
• 卷：7
• 期：51
• 页码：28035-28041
• 全文大小：403K
• ISSN：1944-8252

文摘

Conjugated polymers are widely used materials in organic photovoltaic devices. Owing to their extended electronic wave functions, they often form semicrystalline thin films. In this work, we aim to understand whether distribution of crystallographic orientations affects exciton diffusion using a low-band-gap polymer backbone motif that is representative of the donor/acceptor copolymer class. Using the fact that the polymer side chain can tune the dominant crystallographic orientation in the thin film, we have measured the quenching of polymer photoluminescence, and thus the extent of exciton dissociation, as a function of crystal orientation with respect to a quenching substrate. We find that the crystallite orientation distribution has little effect on the average exciton diffusion length. We suggest several possibilities for the lack of correlation between crystallographic texture and exciton transport in semicrystalline conjugated polymer films.