Thin-film transistor-driven vertically stacked full-color organic light-emitting diodes for high-resolution active-matrix displays

Abstract

Thin-film transistor (TFT)-driven full-color organic light-emitting diodes (OLEDs) with vertically stacked structures are developed herein using photolithography processes, which allow for high-resolution displays of over 2,000 pixels per inch. Vertical stacking of OLEDs by the photolithography process is technically challenging, as OLEDs are vulnerable to moisture, oxygen, solutions for photolithography processes, and temperatures over 100°C. In this study, we develop a low-temperature processed Al 2 O 3 /SiN x bilayered protection layer, which stably protects the OLEDs from photolithography process solutions, as well as from moisture and oxygen. As a result, transparent intermediate electrodes are patterned on top of the OLED elements without degrading the OLED, thereby enabling to fabricate the vertically stacked OLED. The aperture ratio of the full-color-driven OLED pixel is approximately twice as large as conventional sub-pixel structures, due to geometric advantage, despite the TFT integration. To the best of our knowledge, we first demonstrate the TFT-driven vertically stacked full-color OLED.

Integration of synaptic phototransistors and quantum dot light-emitting diodes for visualization and recognition of UV patterns

“…However, there are still challenges relevant to the QLED fabrication including quantum dot patterning, material stability, and solvent orthogonality. Therefore, unconventional patterning techniques and various encapsulation strategies compatible with conventional Si fabrication processes need to be explored ( 53 , 54 ). In addition, as a future research topic, the development of an SPD with threshold switching characteristics would be helpful to reduce hardware complexity and improve efficiency of the SPTr-QLED.…”

Vertically Integrated Electronics: New Opportunities from Emerging Materials and Devices

“…i Current-luminance characteristics of vertically stacked TFT-driven full-color OLEDs in which R, G, and B pixels. j Multi-color realization through R, G, and B combination of TFT-driven vertically stacked full-color OLED [ 119 ]. Copyright © 2020, Springer Nature …”

“…To meet the requirements for future display systems such as augmented reality (AR) and virtual reality (VR), a high-resolution display is highly recommended. Choi et al [ 119 ] developed a vertically stacked OLED system by using intermediate electrodes. The transparent indium zinc oxide (IZO) intermediate electrodes were patterned by the photolithographic process to achieve a finely patterned, high-resolution display.…”

High Performance Yellow Phosphorescent Organic Light-Emitting Diodes Based on an Efficient Carriers Regulating Structure with Iridium Complex as Electron Manager

“…Organic light-emitting diodes (OLEDs) have been rapidly developed since the first demonstration of an efficient organic electroluminescent (EL) device by Tang . To date, some OLED displays and lighting products have trickled into the commercial market. − As one of the milestone discoveries in the OLED field, the pioneering reports of electro-phosphorescence from organometallic complexes have showed enormous potential for developing high-performance phosphorescent OLEDs, where 100% internal quantum efficiency can be realized by spin–orbit coupling caused by heavy metal atom effect. − In the past 20 years, active studies in the fields of materials synthesis and device design have supported the development of phosphorescent OLEDs. − Although phosphorescent OLEDs have realized relatively higher performances in comparison to other kinds of OLEDs, the unsatisfied efficiency and worse efficiency roll-off are still the inextricable topics which might limit the further development toward rapidly gaining a market share in the coming years.…”