Dipole Layer Formation by Surface Segregation of Regioregular Poly(3-alkylthiophene) with Alternating Alkyl/Semifluoroalkyl Side Chains

作者：Geng Yanfang; Wei Qingshuo; Hashimoto Kazuhito^*; Tajima Keisuke

来源：Chemistry of Materials, 2011, 23(18): 4257-4263.

DOI：10.1021/cm2018423

• conjugated polymers
• organic electronics
• structure-property relationship
• thin films
• self-assembly

A regioregular poly(3-alkylthiophene) with alternating alkyl/semifluoroalkyl side chains (P3DDFT) spontaneously segregates on the surface of poly(3-dodecylthiophene) (P3DDT) during a spin-coating process and forms a thin fluoroalkyl layer with a thickness of less than 3 nm. This surface layer is as dense as fluoroalkyl-based self-assembled monolayers (SAMs) on metals, as demonstrated by angle-dependent X-ray photoelectron spectroscopy and water contact angle measurements. The semifluoroalkyl chains aligned at the air/solid interface form a large molecular dipole moment that continuously shifts the ionization energy by as much as +1.8 eV depending on the surface density of P3DDFT. This can be a novel approach to controlling the energy-level alignment at organic/(in)organic interfaces, analogous to the work function shifts of metals induced by the formation of SAMs.

• 出版日期2011-9-27
• 单位北京理工大学