Templating Highly Crystalline Organic Semiconductors Using Atomic Membranes of Graphene at the Anode/Organic Interface

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• 作者：Susmit Singha Roy ; Dominick J. Bindl ; Michael S. Arnold
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2012
• 出版时间：April 5, 2012
• 年：2012
• 卷：3
• 期：7
• 页码：873-878
• 全文大小：350K
• 年卷期：v.3,no.7(April 5, 2012)
• ISSN：1948-7185

文摘

Charge and energy transport in organic semiconductors is highly anisotropic and dependent on crystalline ordering. Here, we demonstrate a novel approach for ordering crystalline organic semiconductors, with orientations optimized for optoelectronics applications, by using a single monolayer of graphene as a molecular template. We show, in particular, that large-area graphene can be integrated on metals and oxides to modify their surface energies and used to template copper phthalocyanine (CuPc), a prototypical organic semiconductor. On unmodified substrates, thermally evaporated films of CuPc are small-grained, and the molecules are in the 鈥渟tanding-up鈥?(100) orientation. On graphene modified substrates, CuPc is templated in favorable 鈥渓ying-down鈥?(112虆) and (012虆) orientations with drastically larger crystal sizes. This results in an 86% increase in the absorption coefficient at 700 nm and should furthermore result in enhanced energy and charge transport. The use of highly conductive and transparent (>95%) graphene membranes as templates is expected to be a foundation for developing future planar and nanostructured organic light-emitting diodes and organic photovoltaics with improved performance.

Keywords:

charge transport; organic semiconductor; template; graphene; photovoltaic