Initiated and oxidative chemical vapor deposition: a scalable method for conformal and functional polymer films on real substrates

Abstract

Chemical vapor deposition (CVD) is a widely-used technology for the preparation of conformal and defect-free inorganic thin films with systematically tunable properties. Polymers are a desirable class of materials for surface modification because of their low cost, wide array of chemical and physical functionality and mechanical flexibility. Initiated and oxidative chemical vapor deposition (iCVD and oCVD) are polymer CVD methods that combine the benefits of CVD processing with the possibilities of polymeric materials. Using these technologies, our laboratory has synthesized a number of functional, biocompatible and electrically conducting polymers as thin films on micro- and nano-structured surfaces. This Perspective will review recent advances in these areas and highlight devices and applications that utilize iCVD and oCVD polymers.

Direct Monolithic Integration of Organic Photovoltaic Circuits on Unmodified Paper

“…[17][18][19][20][21] Figure 1 b compares representative current densityvoltage characteristics for individual devices on glass, differing only in anode structure: (i) oCVD PEDOT (50 nm), (ii) indium perform comparably to the devices with conventional ITO anode structures (ii and iv), and both oCVD PEDOT and PEDOT:PSS devices exhibit improved open-circuit voltage (0.48 V) relative to those on bare ITO (0.41 V). [ 17 , 23 , 24 ] Both oCVD PEDOT and PEDOT:PSS have comparable work functions ( ∼ 5.2 eV); [ 11 ] however, the conductance of oCVD PEDOT thin fi lms is several orders of magnitude more conductive than the PEDOT:PSS (CLEVIOS™ P VP AI 4083) buffer layer ( < 10 S · cm − 1 ), [ 12 ] which contributes to the higher observed fi ll factor ( > 0.6) in the devices with ITO/oCVD PEDOT electrodes (iii) due to the lower device series resistance (1.2 Ω · cm 2 vs. 4.2 Ω · cm 2 ). For the ITOfree oCVD electrodes (i), the trade-off between sheet resistance and transparency with thickness accounts for the decrease in the fi ll factor (0.54) due to series resistance (4.4 Ω · cm 2 ) and the short-circuit current (3.8 mA · cm − 2 ) relative to (ii) (Supporting Table S1).…”

Moisture barrier enhancement by spontaneous formation of silicon oxide interlayers in hot wire chemical vapor deposition of silicon nitride on poly(glycidyl methacrylate)

“…Furthermore, this method provides an elegant method for the deposition of an oxide material without using oxidative gasses. A requirement for the success of this method might be the use of iCVD for the deposition of polymers with epoxy groups, which ensures an almost 100% retention of functional groups, in this case the very important epoxide ring and double bonded oxygen group [14].…”

Self‐Aligned Micropatterns of Bifunctional Polymer Surfaces with Independent Chemical and Topographical Contrast

“…[13,14] In iCVD, vapor-phase monomers and initiators flow into a custom-built vacuum reactor. Radical species are generated either by heated filaments or ultraviolet light; these radical species react with monomers adsorbed at a cooled substrate to initiate a polymerization.…”

“…iCVD has been used to deposit a wide variety of polymers and copolymers, including click-functional, alternating, biocompatible, crosslinked, stimuli responsive and fluorinated polymers. [13] The height of the growing film is monitored in real-time using laser interferometry. This enables the surface to be patterned not only chemically but also topographically.…”

“…For a more extensive description of the process, we direct the reader to a recent review. [13] A 2000 mesh TEM copper grid (Ted Pella, G2000) with 7.5 mm holes and 5 mm bars was used as the contact mask for patterning. In order to obtain intimate contact between the mask and the polymer film, a drop of liquid, usually water or acetone, was placed on top of the mask and gentle pressure was applied with either a cotton swap or a flat piece of silicon.…”