Accuracy control for roll and sheet processed printed electronics on flexible plastic substrates

Abstract

For the first time, the necessity to thermally pre-treat ubiquitously used PET substrates for printed electronics, to improve dimensional stability during manufacturing, is clearly defined. The experimental results have proven this phenomenon for both roll-to-roll (R2R) and sheet-to-sheet (S2S) processing of printed electronics. The next generation of electronics manufacturing has pushed the boundaries for low-cost, flexible, printed, and mass produced electronic components and systems. A driving force, and enabling production method, are the R2R printing presses. However, to produce electronics with increasing complexity and high yield in volume production, one must have a highly accurate process. In this article, R2R processing accuracy of printed electronics is evaluated from the point of dimensional accuracy of the flexible polyester substrate (DuPont Teijin Films’ PET Melinex ST504 with and without indium tin oxide, Melinex ST506, and Melinex PCS), precision of printing, and accuracy of layer-to-layer registration with stages that involve tension and elevated temperatures. This study has confirmed that dimensional changes during R2R processing will occur only in the first processing stage and that if a thermal pre-treatment run for the substrate is made—at identical temperature and tension of the processing stage—there is improved stability originating from a new-level strain in the crystalline PET film structure and freezing it in at the tensions and temperatures it is exposed to (i.e. 1400 μm machine direction stretching reduced to 8 μm). Furthermore, it is explained how the dimensional accuracy can be improved and reproducibly maintained in multilayer printing of electronics devices such as organic photovoltaics (OPV). These devices provide a valuable baseline of how the layer-to-layer alignment accuracy plays a crucial role in fully printed electronics devices, which lessons can be applied in all aspects of this field including hybrid systems and system fabrication involving multiple processing methods.

Dispersion stability of tin(IV) oxide nanoparticles in polar solvents and water aided by ultrasonication

“…For this purpose, SnO 2 is usually dispersed in a liquid medium to prevent agglomeration and made into thin films 26,27) -an interface suited for many other potential applications such as flexible and printed electronics. 28,29) Ultrasonication is a technique that applies acoustic/ultrasound energy at frequencies usually higher than 20 kHz to facilitate the disruption of NPs' agglomerates through a process called cavitation-implosion of bubbles that results in the break down of large size NPs, enabling the NPs to mix homogeneously with the liquid medium and form a dispersed solution with high stability. Here, the stability of the dispersion is the capability of the NPs to remain distributed in the liquid solvent with no developed clusters over a prolonged time period.…”

Flexible Organic Photovoltaics with Star‐Shaped Nonfullerene Acceptors End Capped with Indene Malononitrile and Barbiturate Derivatives

“…Organic photovoltaics (OPVs) are an emerging third-generation class of solar cells that have proven to be an advantageous PV harvesting method due to their potential low cost, flexibility, lightweight, and color tunability, combined with simple and scalable manufacturing. [1][2][3] The active layer of OPVs usually consists of an electron donor and electron acceptor, which are blended together to form a so-called bulk heterojunction (BHJ) structure. Normally, the electron donor is a p-type conjugated polymer while the electron acceptor is an n-type fullerene or nonfullerene derivative.…”

Effect of accelerated aging on properties of biobased polymer films applicable in printed electronics

“…Heat-stabilized, semicrystalline polyethylene terephthalate (PET) is ubiquitously used as a substrate for PE/FHE applications because of its strength, stiffness, and thermal stability. 22 Substrate aging in outdoors or indoors with direct solar radiation through windows have impact on the performance, reliability, and lifetime of electronic devices. For that reason, it is important to assess the impacts of climatic stresses on the properties of the plastic films for printed and hybrid electronics.…”

“…Printed electronics (PE) and flexible hybrid electronics (FHE) with increasing complexity need substrate materials those can promote device stability. Heat‐stabilized, semicrystalline polyethylene terephthalate (PET) is ubiquitously used as a substrate for PE/FHE applications because of its strength, stiffness, and thermal stability 22 . Substrate aging in outdoors or indoors with direct solar radiation through windows have impact on the performance, reliability, and lifetime of electronic devices.…”