Measurement of Small Molecular Dopant F4TCNQ and C60F36 Diffusion in Organic Bilayer Architectures

详细信息    查看全文

• 作者：Jun Li ; Chris W. Rochester ; Ian E. Jacobs ; Stephan Friedrich ; Pieter Stroeve ; Moritz Riede ; Adam J. Moulé
• 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：28420-28428
• 全文大小：646K
• ISSN：1944-8252

文摘

The diffusion of molecules through and between organic layers is a serious stability concern in organic electronic devices. In this work, the temperature-dependent diffusion of molecular dopants through small molecule hole transport layers is observed. Specifically we investigate bilayer stacks of small molecules used for hole transport (MeO-TPD) and p-type dopants (F4TCNQ and C₆₀F₃₆) used in hole injection layers for organic light emitting diodes and hole collection electrodes for organic photovoltaics. With the use of absorbance spectroscopy, photoluminescence spectroscopy, neutron reflectometry, and near-edge X-ray absorption fine structure spectroscopy, we are able to obtain a comprehensive picture of the diffusion of fluorinated small molecules through MeO-TPD layers. F4TCNQ spontaneously diffuses into the MeO-TPD material even at room temperature, while C₆₀F₃₆, a much bulkier molecule, is shown to have a substantially higher morphological stability. This study highlights that the differences in size/geometry and thermal properties of small molecular dopants can have a significant impact on their diffusion in organic device architectures.