Dependence of Crystallite Formation and Preferential Backbone Orientations on the Side Chain Pattern in PBDTTPD Polymers
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- 作者：Abdulrahman El Labban ; Julien Warnan ; Cl茅ment Cabanetos ; Olivier Ratel ; Christopher Tassone ; Michael F. Toney ; Pierre M. Beaujuge
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2014
- 出版时间：November 26, 2014
- 年：2014
- 卷：6
- 期：22
- 页码：19477-19481
- 全文大小：336K
- ISSN：1944-8252
文摘
Alkyl substituents appended to the 蟺-conjugated main chain account for the solution-processability and film-forming properties of most 蟺-conjugated polymers for organic electronic device applications, including field-effect transistors (FETs) and bulk-heterojunction (BHJ) solar cells. Beyond film-forming properties, recent work has emphasized the determining role that side-chain substituents play on polymer self-assembly and thin-film nanostructural order, and, in turn, on device performance. However, the factors that determine polymer crystallite orientation in thin-films, implying preferential backbone orientation relative to the device substrate, are a matter of some debate, and these structural changes remain difficult to anticipate. In this report, we show how systematic changes in the side-chain pattern of poly(benzo[1,2-b:4,5-b鈥瞉dithiophene鈥?i>alt鈥搕hieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) polymers can (i) influence the propensity of the polymer to order in the 蟺-stacking direction, and (ii) direct the preferential orientation of the polymer crystallites in thin films (e.g., 鈥渇ace-on鈥?vs 鈥渆dge-on鈥?. Oriented crystallites, specifically crystallites that are well-ordered in the 蟺-stacking direction, are believed to be a key contributor to improved thin-film device performance in both FETs and BHJ solar cells.