During the last 3,5 years, on the way to the final project demonstrators, the consortium has worked intensively together, forming a strong network between the partners, which opens also the way for future joint projects and collaborations. Expertise in particular for material and process development has been built up, and the results have been disseminated, for example in various peer-reviewed papers, conference talks and posters, press releases, folders, a project video, the project homepage, newspaper articles and social media posts. A patent has been filed, and partners plan post project explanation of their individual results.
Hi-Accuracy has started on 01-04-2020 and the final second period has started on 01-10-2021 and ended on 30-09-2023, which included a 6 months extension owing to the pandemic situation particularly during the first period.
As it became clear, which technologies are suitable to develop a manufacturing process for the 1” 300 ppi full colour RGB quantum dot active matrix display, and which technologies were further developed to manufacture components of the demonstrator. The main goals included the quantum dots to be electro-luminescent (light emission induced by a current instead of a backlight) and the optically active materials to be printed by electro-static jet printing, a method, which differs from well-known inkjet by the physical nozzle being replaced by a suitable electrostatic field. The active matrix backplane of the display, which contains the electronics switching on and off each pixel was manufactured by photo-lithography as a back-up for printing methods originally not only planned for the frontplane but also for the backplane.
The demonstrator displays and all components thereof were manufactured on a 25 µm thin polymer substrate to enable bending that is sufficient to wrap the display around a wrist or mount it in the interior of a car, as specified by end-users. The active-matrix electro-luminescent quantum-dot LED requires a barrier against humidity and oxygen in air, which has been applied on the substrate at the bottom and on the top of the layered material stack by Atomic Layer Deposition (ALD), after failing attempts to apply novel non-vacuum techniques.
Additional frontplane demonstrators were manufactured without active matrix addressing to show the potential resolution of ESJET printing quantum dot and electron transport layers.
Apart from the demonstrators, there were components of the backplane manufactured by additive methods. Reverse Offset Printing (ROP) is a scalable roll-to-sheet process that was employed to manufacture the organic semi-conductor and gate-electrodes of organic thin film transistors (OTFTs)
Nanoimprint Lithography pre-structured trenches that were filled by ESJET printed nano-Ag-inks to form the source-drain electrodes of OTFTs in pixel driver circuits.
Finally a number of fundamental printing tests of layered materials were carried out to evaluate processes and materials.
More information on the project can be found on the project homepage www.hi-accuracy.eu which is regularly updated with the latest news. Final project results will be presented by consortium partners to the public at major scientific conferences e.g. LOPEC 2024.
