Combining Vapor Phase Polymerization and Screen Printing for Printed Electronics on Flexible Substrates

Abstract

and have led to several commercial products such as inks, sensors, and displays.Conductive polymers can be synthesized by several methods, each with their own set of advantages and disadvantages. Chemical polymerization is the simplest method, requiring only the reagents necessary for the polymerization and a container, but generally results in poor properties. Electrochemical polymerization is a more controlled polymerization method (via the voltage and current), but requires a problematic three-electrode set up when considering large areas and upscaling. One polymerization technique that has shown promise, both for resulting in good conductive polymer properties and the potential for large area manufacturing, is vapor phase polymerization (VPP). [3,4] VPP uses a liquid oxidant that polymerizes a vapor monomer. The oxidant can be deposited using many different techniques, the most common method is spin coating, which results in very smooth and homogenous layers. [5][6][7][8] Performing VPP on spin-coated oxidant films has been shown to provide conductive polymers of impressive electronic properties and relatively large scale (10 cm 2 ). [9,10] However, its ability to coat one substrate at a time and the material waste makes spin coating unsuitable for hundreds of devices or truly large scale (≈dm 2 − m 2 ).Various deposition methods of the oxidant followed by VPP have been published to push the resolution of patterns possible via dip pen lithography [11] or for increasing the possibility for largescale manufacturing via inkjet printing. [12] However, truly scalable conductive polymer films fabricated by VPP have yet to be shown.Screen printing is one industrial standard deposition technique that can be truly scalable in either a sheet-by-sheet or roll-to-roll process. This technique allows pattern resolutions of at least 100 µm (with 100 µm spacing) and the ink deposition is performed within seconds. Screen printing has been used extensively for display, [13] sensor, [14] energy storage, [15] and transistor [16] applications due to the ability of over-printability, alignment at high accuracy, and registration marks allowing layer-by-layer deposition of functional inks.The combination of screen printing and the VPP process will permit all-printed devices to be fabricated at high resolution, which opens the possibilities of commercialization due to the cost-effective deposition technique. Previous reports combining Large area manufacturing of printed electronic components on ~A4-sized substrates is demonstrated by the combination of screen printing and vapor phase polymerization (VPP) into poly(3,4-ethylenedioxythiophene) (PEDOT).The oxidant layer required for the polymerization process is screen printed, and the resulting conductive polymer patterns are manufactured at high resolution (100 µm). Successful processing of several common oxidant species is demonstrated, and the thickness can be adjusted by altering the polymerization time. By comparing the polymer films of this work to a commercial PEDOT:PSS (PEDOT d...

Electrochromic Displays Manufactured by a Combination of Vapor Phase Polymerization and Screen Printing

“…From the previous report [ 18 ] we have developed an oxidant ink suitable for the VPP of EDOT, which was composed of 6 wt% Fe(Otf) and 37.5 wt% PEG‐PPG‐PEG in water. It was also shown that increasing the thickness, and therefore the absorbance, could be achieved by increasing the polymerization time of the VPP process.…”

“…Recently, we have shown that using VPP combined with screen printing allows for PEDOT to be formed without incorporation of the polymer into the ink. [ 18 ] Instead, the oxidant species (an iron salt) is formulated into an ink and after deposition by screen printing, the oxidant is exposed to a monomer vapor, and after a washing step the VPP film is ready for use in displays, transistors, or other printed electronic components. The combinations of screen printing and VPP, and the steps for the successful patterning of VPP conductive polymers, are outlined in Figure .…”

“…In the previous study, [ 18 ] we introduced the idea of screen printing an oxidant ink composed of iron trifluoromethane sulfonate (FeOtf) (iron tosylate and iron chloride were also trialed) and PEG‐PPG‐PEG with water as the solvent. Once the oxidant ink was deposited (in various complex screen designs), the samples were exposed to EDOT monomer vapor and once completed and washed, the films were characterized and incorporated into all‐printed organic electrochemical transistors.…”

“…[16,17] Recently, we have shown that using VPP combined with screen printing allows for PEDOT to be formed without incorporation of the polymer into the ink. [18] Instead, the oxidant species (an iron salt) is formulated into an ink and after deposition by screen printing, the oxidant is exposed to a monomer vapor, and after a washing step the VPP film is ready for use in displays, transistors, or other printed electronic Smart label technology such as indicators is a growing field due to society's demand for Internet of Things devices. New materials and technologies are continuously being discovered and developed in order to provide better resolution, better performance, or more environmentally friendly devices.…”

Low-Temperature Soldering of Surface Mount Devices on Screen-Printed Silver Tracks on Fabrics for Flexible Textile Hybrid Electronics

“…Printing technologies have evolved, providing a gradual improvement of the resulting printed circuits. The technologies for printing, such as screen printing [ 9 , 10 ], inkjet printing [ 11 ], or roll-to-roll printing [ 12 ], including flexography [ 13 , 14 ], gravure [ 15 , 16 ], or offset [ 17 ], have adapted to the needs of this kind of technology.…”