All inkjet‐printed 6.95″ 217 ppi active matrix QD‐LED display with RGB Cd‐free QDs in the top‐emission device structure

Abstract

Electroluminescence quantum dot devices (QD‐LEDs) show the promise in the development of future displays. For commercialization, the top emission device structure is more advantageous than the bottom emission device structure to realize the high aperture ratio full color displays. Moreover, it is essential to understand not only the device structure and characteristics of QD‐LEDs but also the challenging issues in inkjet‐printed devices. Here, we demonstrated the world first all inkjet‐printed Cd‐free active matrix QD‐LEDs based on getting over the hurdles of all inkjet printing process. Especially, we have fabricated QD‐LED devices by stacking 4‐soluble layers without intermixing and studied the factors affecting QD efficiency and QD printing and the influence of ETL solvent on QD. Inkjet‐printed QD‐LED devices have achieved 8 cd/A, 70 cd/A, and 8 cd/A current efficiency of red, green, and blue, respectively, on the basis of 250 nits of full white RGB panels. We believe that our work clarifies an encouraging step toward the practical application of Cd‐free based QD‐LED displays.

2D PEA2SnI4 Inkjet-Printed Halide Perovskite LEDs on Rigid and Flexible Substrates

“… 16 Inkjet printing is believed to be the most feasible tool for patterning full color QD-LED displays for mass production. 17 …”

“…It does not offer spatial resolution for the deposition of multiple LEDs in large areas, and a major amount of the precursors is wasted. , In contrast, inkjet printing is an emerging technology suitable to achieve smooth, uniform, and pinhole free thin films that can be exploited to produce low-cost, large area, and even foldable devices and arrays . Inkjet printing is believed to be the most feasible tool for patterning full color QD-LED displays for mass production …”

Heteroepitaxial chemistry of zinc chalcogenides on InP nanocrystals for defect-free interfaces with atomic uniformity

“…To investigate these challenges, we chose the widely used zinc oleate [Zn(OA) 2 ] and trioctylphosphine selenide (SePR’ 3 ; R’ is octyl) as the heteroepitaxy precursors to analyse the sequence of ZnSe epilayer formation on the oleate-capped InP NCs (InP–OA; the radius of 2.4 or 3.3 nm). Notably, InP NCs have been extensively studied since the inception of semiconductor NCs and are of practical importance in the display industry as colour-converting materials 30 , 35 . Although the PL QY of InP NCs has recently approximated unity through InP/ZnSe/ZnS core/shell/shell heterostructures 29 , 30 , 36 , 37 , detailed research on the heteroepitaxy chemistry at the molecular level has not been established.…”

Development of the ink‐jet printing technology for 55‐inch 8K AMQLED display

“…At the same time, the high boiling point solvent should be preferred to prevent the clogging of nozzle caused by rapid evaporation of solvent and uneven film caused by premature evaporation of ink droplet solvent. 15 The quantum dot material in the ink is Cd-based gradient alloy quantum dot. The choice of ink solvent has a great influence on the printing process and determines the morphology of the printing film.…”