Surface dipole engineering for conducting polymers

The first example of systematic control of the work function of a conducting polymer is illustrated for PEDOT:PSS. A nanometer-thick film of TiO2 is formed on the PEDOT:PSS surface and forms an adhesion layer to bond phosphonic acids to the polymer; the work function of the PEDOT:PSS (ΦPEDOT:PSS) is adjusted by choice of phosphonic acid over a range of approximately 0.8 eV, and ΔΦPEDOT:PSS correlates strongly with the calculated gas-phase dipole moments of the phosphonates.

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► A nanometer thick adhesion layer can be synthesized on the surface of a conducting polymer.
► Self-assembled monolayers of phosphonates can be formed on this adhesion layer.
► The dipole moments of the phosphonates can be manipulated to control the work function of the conducting polymer.
► Ultraviolet photoelectron spectroscopic analysis supports Kelvin probe measurements of work function changes.