Three-Dimensional (3D) Device Architectures Enabled by Oxidative Chemical Vapor Deposition (oCVD)

Abstract

For fabricating devices with three-dimensional (3D) architectures, oxidative Chemical Vapor Deposition (oCVD) offers conformal nanocoatings of polymers with designable composition. Pure, uniform and pinhole-free oCVD layers are achievable with sub-10 nm thickness and sub-1 nm roughness. The low substrate temperature used for oCVD, allows direct deposition onto the thermally sensitive substrates desired for flexible and wearable devices. The oCVD polymers can graft to the underlying material. The covalent chemical bonds to the substrate create a robust interface that prevents delamination during the subsequent device fabrication steps and exposure to the environmental conditions of device operation. Both electrically conducting and semiconducting polymers have been synthesized by oCVD. Small ions act as dopants. The oCVD process allows for systematic tuning of electrical, optical, thermal, and ionic transport properties. Copolymerization with oCVD can incorporate specific organic functional groups into the resulting conjugated organic materials. This short review highlights recent examples of using oCVD polymer to fabricate organic and hybrid organic-inorganic devices. These optoelectronic, electrochemical, and sensing devices utilize 3D architectures made possible by the conformal nature of the oCVD polymers. Table of Contents: 1 Introduction 2 oCVD Chemistry and Process 3 Optoelectronic Devices 4 Electrochemical Devices 5 Sensing Devices 6 Conclusion

oCVD PEDOT-Cl Thin Film Fabricated by SbCl5 Oxidant as the Hole Transport Layer to Enhance the Perovskite Solar Cell Device Stability

“…Oxidative chemical vapor deposition (oCVD) has recently emerged as an efficient and PSS-free technique for fabricating high-quality conformal PEDOT thin films with excellent optoelectronic properties, enabling their application as a more stable HTL. The oCVD method for producing conjugated conducting/semiconducting polymer thin films involves the reaction of gas-phase reactants, including monomer and oxidant, in contrast to conventional solution-based methods that rely on spin-coating. ,− By circumventing the limitations imposed by surface tension in solution-based manufacturing, the oCVD technique demonstrates its potential for enabling the fabrication of highly conformal PEDOT coatings in advanced energy devices and wearable electronics. ,,, Furthermore, the oCVD method stands out as a versatile manufacturing method to fabricate polymers with low to no solubility. In addition, the oCVD method is compatible with large-scale production through the roll-to-roll (R2R) process.…”

“…In addition, the oCVD method is compatible with large-scale production through the roll-to-roll (R2R) process. Conductive polymers fabricated using the oCVD method demonstrate advantages such as low defect densities, precise control over nanoscale thickness, compatibility with low deposition temperatures for growth on thermally sensitive substrates, and the ability to conformally coat intricate nanostructures. ,,, The stable PEDOT coatings fabricated using the oCVD method have been successfully applied to various ordinary sensitive substrates, such as papers, , textiles, membranes, carbon fibers, and graphene. , The oCVD method’s ability to fabricate highly conformal conducting polymer thin films is a significant asset for advanced technologies, including solar cell applications and electrochemical energy storage devices. ,, This advantage is leveraged by applying conformal coatings on artificially textured surfaces, effectively increasing the available surface area for improved light absorption by the photoactive layer …”

“…Solid oxidants are commonly used in the oCVD method, while the adoption of liquid oxidants has been developed recently and represents a novel approach with distinct benefits including direct integration of conductive polymer thin films into device applications as a one-step, dry process without the need for postdeposition rinsing. When utilizing solid oxidants like FeCl 3 in the fabrication of conducting polymer thin films by the oCVD method, low-volatility oxidation byproducts are generated, necessitating post-treatment methods such as methanol and acidic rinsing for enhanced electrical conductivity. ,,,, Conversely, with liquid oxidants like SbCl 5 , no postdeposition acidic rinsing is required, offering cost advantages and compatibility with solvent- and temperature-sensitive substrates. ,, Furthermore, the flow rate of liquid oxidant can be precisely controlled, providing an advantage over solid oxidants, where control over the flow rate is limited during insertion into the crucible placed inside the reactor …”

“…18,23−29 By circumventing the limitations imposed by surface tension in solutionbased manufacturing, the oCVD technique demonstrates its potential for enabling the fabrication of highly conformal PEDOT coatings in advanced energy devices and wearable electronics. 6,25,30,31 Furthermore, the oCVD method stands out as a versatile manufacturing method to fabricate polymers with low to no solubility. In addition, the oCVD method is compatible with large-scale production through the roll-to-roll (R2R) process.…”

“…2,6,25,37,45 Conversely, with liquid oxidants like SbCl 5 , no postdeposition acidic rinsing is required, offering cost advantages and compatibility with solvent-and temperaturesensitive substrates. 2,25,30 Furthermore, the flow rate of liquid oxidant can be precisely controlled, providing an advantage over solid oxidants, where control over the flow rate is limited during insertion into the crucible placed inside the reactor. 2 Here we report the first integration of as-deposited oCVD PEDOT thin films grown by liquid SbCl 5 oxidant as the HTL in PSCs.…”