Aerosol jet printing of PEDOT:PSS for large area flexible electronics

Abstract

We investigate and optimize the Aerosol Jet Printing of PEDOT:PSS by studying the role of parameters determining the final quality of the printed features. Printing thin films of organic materials requires a high control in the deposition process to control the morphology/structure of the films that determine the electrical and functional performance of organic devices. We studied aerosol jet printed lines of the PEDOT:PSS semiconductive polymer on flexible Kapton substrates. We choose the focus ratio, defined as the ratio between the sheath and carrier gas flow rates, as the main parameter that best characterizes the process and hence the characteristics of printed lines. A detailed analysis of the line width and thickness, as a function of the focus ratio and carrier gas flow for different nozzle sizes and sheath gas flow rates, is reported. The edge profile definition of printed PEDOT:PSS lines has been found to be affected by a combination of overspray, typical of aerosol deposition, and pinholes due to the Kapton/PEDOT:PSS interaction, while their core profile results to be almost defects free. An optimal printing window for different nozzle sizes has been determined in terms of a minimization of overspray/pinholes effects with respect to the whole line width. Finally, an array of whole-plastic, planar Organic Electrochemical Transistors, having both the channel and the gate electrode made of PEDOT:PSS, has been manufactured using the best combination of process parameters. Transistors have been characterized for different channel/gate area ratios and the transconductance analysed as a function of channel to gate area.

Rapid prototyping of 3D Organic Electrochemical Transistors by composite photocurable resin

“…The maximum of g m linearly increases from 550 µS at V ds = − 100 mV to 2.5 mS at V ds = − 600 mV where it saturates, while the peak position moves towards negative V gs , as expected from the high volume capacitance due to the thick active layer of the device 34 , 36 . As reported in Table 1 , it is expected that maximum transconductance can vary a lot depending on the 3D printing fabrication process, therefore the found values are comparable or even higher with respect to others reported in literature 19 , 20 , while higher values of g max are achieved for lower thickness 21 , 37 . In our case, the thickness of the channel is higher than planar one but, the assessed low transconductance value is clearly due to the properties of the resin composite that works on the basis of the PEDOT particles interconnections inside the insulating PEGDA matrix.…”

“… Fabrication Techniques Channel dimension W/L/t (μm) Materials gmax (mS) I ON /I OFF References Stereolithopgraphy 700/1900/500 PEGDA:PEDOT 2.5 2.79 ± 1.6 ⋅10 3 This work Aerosol-jet printing 200/200/0.2 PEDOT:PSS 0.52 ND Ref. 19 Laser sintering 1,000/15,000/1,000 PEDOT:PSS 2 2 Ref. 20 FDM/direct writing 3D 1,000/1,600/7.1 PEDOT:PSS 31.8 1.33⋅10 3 Ref.…”

“…3D printing methods for the development of electronic devices actually provide 2D structures (e.g. ink-jet 18 , aerosol-jet 19 ) or 3D structures implemented upon multistep processes 20 and by Fused Deposition Modeling (FDM) and micro-dispensing 21 – 23 . This work introduces a non-trivial novelty consisting in demonstrating the fabrication of multi-materials 3D objects, which are intrinsically equipped with specific physical properties and can be manufactured in-line by combining 3D SL techniques and engineered resins.…”

Universal Spray-Deposition Process for Scalable, High-Performance, and Stable Organic Electrochemical Transistors

“…One promising alternative deposition technique is spray-coating, which involves the formation of active layers by sprayed droplets deposition. [24][25][26] The spray-coating process also allows lower material losses during deposition and is easily scalable for large area electronics. [27][28][29] Another advantage of spray-coating is that it enables the deposition of films on non-flat surfaces.…”

Recent Technological Advances in Fabrication and Application of Organic Electrochemical Transistors

“…Nevertheless, it is also an open challenge to control the edge profile instabilities of printed lines, since AJP process is highly affected by several parameters including the overspray issue and ink/substrate compatibility, thus causing a reproducibility problem. [ 89 ] This technique has been widely explored to prepare the active layers for electrolyte‐gated transistors (EGTs) and OECTs. [ 89–93 ] Attractive features of AJP‐based transistors such as high output conductance, low operation voltage and fast switching times have been demonstrated, thus exhibiting promising application in printed circuits.…”