Vapor Phase Polymerization of EDOT from Submicrometer Scale Oxidant Patterned by Dip-Pen Nanolithography

Abstract

Some of the most exciting recent advances in conducting polymer synthesis have centered around the method of vapor phase polymerization (VPP) of thin films. However, it is not known whether the VPP process can proceed using significantly reduced volumes of oxidant and therefore be implemented as part of nanolithography approach. Here, we present a strategy for submicrometer scale patterning of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) via in situ VPP. Attolitre (10 -18 L) volumes of oxidant "ink" are controllably deposited using dip-pen nanolithography (DPN). DPN patterning of the oxidant ink is facilitated by the incorporation of an amphiphilic block copolymer thickener, an additive that also assists with stabilization of the oxidant. When exposed to EDOT monomer in a VPP chamber, each deposited feature localizes the synthesis of conducting PEDOT structures of several micrometers down to 250 nm in width. PEDOT patterns are characterized by atomic force microscopy (AFM), conductive AFM, two probe electrical measurement, and micro-Raman spectroscopy, evidencing in situ vapor phase synthesis of conducting polymer at a scale (picogram) which is much smaller than that previously reported. Although the process of VPP on this scale was achieved, we highlight some of the challenges that need to be overcome to make this approach feasible in an applied setting. ABSTRACT: Some of the most exciting recent advances in conducting polymer synthesis have centered around the method of vapor phase polymerization (VPP) of thin films. However, it is not known whether the VPP process can proceed using significantly reduced volumes of oxidant and therefore be implemented as part of nanolithography approach. Here, we present a strategy for submicrometer scale patterning of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) via in situ VPP. Attolitre (10 −18 L) volumes of oxidant "ink" are controllably deposited using dip-pen nanolithography (DPN). DPN patterning of the oxidant ink is facilitated by the incorporation of an amphiphilic block copolymer thickener, an additive that also assists with stabilization of the oxidant. When exposed to EDOT monomer in a VPP chamber, each deposited feature localizes the synthesis of conducting PEDOT structures of several micrometers down to 250 nm in width. PEDOT patterns are characterized by atomic force microscopy (AFM), conductive AFM, two probe electrical measurement, and micro-Raman spectroscopy, evidencing in situ vapor phase synthesis of conducting polymer at a scale (picogram) which is much smaller than that previously reported. Although the process of VPP on this scale was achieved, we highlight some of the challenges that need to be overcome to make this approach feasible in an applied setting.

Patterning and Conductivity Modulation of Conductive Polymers by UV Light Exposure

“…With contact transfer techniques, such as mold transfer printing [6] and dip pen nanolithography [12] , it is possible to achieve sub-micrometer resolution.…”

Flexible and Cellulose-based Organic Electronics

“…Some techniques such as mold transfer printing [62] and dip pen nanolithography [63] have been used to pattern organic semiconductors with sub-micrometer resolution. However, the most commonly used method for high resolution patterning of both organic and inorganic materials is photolithography, which involves the patterning of a light sensitive polymer (photoresist) using UVlight.…”

Nanoscale platinum printing on insulating substrates

“…After plasma reduction, the current flowing through the resulting platinum resistor was measured using a potentiostat (eDAQ EA162) to drive a linear voltage sweep from -10 V to + 10 V. AFM scans of the feature were used to obtain cross-sectional information to calculate resistance. A similar methodology has been followed previously [23].…”

“…[21][22][23][24] Although a slew of methodologies have been developed over the past decade to print gold features via DPN (see reference [25] for a review of DPN metal printing), very few groups have succeeded in depositing platinum at nanoscales. In one interesting approach, an electrochemical fountain pen was used to create free-standing platinum micro-and nano-structures [1,26].…”