Exciton Quenching Close to Polymer−Vacuum Interface of Spin-Coated Films of Poly(p-phenylenevinylene) Derivative

详细信息    查看全文

• 作者：Oleksandr V. Mikhnenko ; Fabrizio Cordella ; Alexander B. Sieval ; Jan C. Hummelen ; Paul W. M. Blom ; Maria Antonietta Loi
• 刊名：Journal of Physical Chemistry B
• 出版年：2009
• 出版时间：July 9, 2009
• 年：2009
• 卷：113
• 期：27
• 页码：9104-9109
• 全文大小：178K
• 年卷期：v.113,no.27(July 9, 2009)
• ISSN：1520-5207

文摘

Polymer−fullerene bilayer heterostructures are suited to study excitonic processes in conjugated polymers. Excitons are efficiently quenched at the polymer−fullerene interface, whereas the polymer−vacuum interface is often considered as an exciton-reflecting interface. Here, we report about efficient exciton quenching close to the polymer−vacuum interface of spin-coated MDMO-PPV (poly[2-methoxy-5-(2′-ethyl-hexyloxy)-p-phenylenevinylene]) films. The quenching efficiency is estimated to be as high as that of the polymer−fullerene interface. This efficient quenching is consistent with enhanced intermolecular interactions close to the polymer−vacuum interface due to the formation of a “skin layer” during the spin-coating procedure. In the skin layer, the polymer density is higher; that is, the intermolecular distances are shorter than in the rest of the film. The effect of exciton quenching at the polymer−vacuum interface should be taken into account when the thickness of the polymer film is on the order of the exciton diffusion length; in particular, in the determination of the exciton diffusion length.