Active‐matrix organic light‐emitting diode displays with indium gallium zinc oxide thin‐film transistors and normal, inverted, and transparent organic light‐emitting diodes

Abstract

Abstract— Active‐matrix organic light‐emitting diode (AMOLED) displays have gained wide attention and are expected to dominate the flat‐panel‐display industry in the near future. However, organic light‐emitting devices have stringent demands on the driving transistors due to their current‐driving characteristics. In recent years, the oxide‐semiconductor‐based thin‐film transistors (oxide TFTs) have also been widely investigated due to their various benefits. In this paper, the development and performance of oxide TFTs will be discussed. Specifically, effects of back‐channel interface conditions on these devices will be investigated. The performance and bias stress stability of the oxide TFTs were improved by inserting a SiOx protection layer and an N2O plasma treatment on the back‐channel interface. On the other hand, considering the n‐type nature of oxide TFTs, 2.4‐in. AMOLED displays with oxide TFTs and both normal and inverted OLEDs were developed and their reliability was studied. Results of the checkerboard stimuli tests show that the inverted OLEDs indeed have some advantages due to their suitable driving schemes. In addition, a novel 2.4‐in. transparent AMOLED display with a high transparency of 45% and high resolution of 166 ppi was also demonstrated using all the transparent or semi‐transparent materials, based on oxide‐TFT technologies.

Single‐source dual‐layer amorphous IGZO thin‐film transistors for display and circuit applications

“…The second demonstrator, a flexible QVGA AMOLED display with an 85‐dpi resolution, was realized in cooperation between Holst Center and Polymer Vision. Hereby, a low‐temperature dual‐layer a‐IGZO TFT backplane with design scheme of 2T1C cell on PEN foil was successfully integrated with inkjet‐printed OLEDs and a thin‐film barrier stack as the encapsulation as shown in the Fig. (a).…”

31-4: Novel Inorganic Electron Injection and Transport Materials Enabling Large-Sized Inverted OLEDs Driven by Oxide TFTs

“…Inverted OLEDs, stable electron injection material, fabrication process It is now a consensus that oxide TFTs represented by IGZO [1,2] are the most promising candidate to drive large-sized OLEDs from a view of performance, scalability and cost. Since oxide TFTs works as n-channel, the favorable device stacking structure needs to change from currently available normal-type driven by p-channel LTPS-TFT to inverted type ( Fig.1) which is excellent in stability and image clarity [3,4]. Top emission type is more favorable to keep high aperture ratio for high resolution pixels.…”

54-3:Invited Paper: Flexible Active-Matrix OLET Display on a Plastic Substrate

“…Organic electroluminescence devices have been widely explored during the past two decades [1][2]. Particularly, active-matrix organic light-emitting diode (AMOLED) displays are expected to be the dominant technology for the next generation flat panel displays [3][4][5][6]. The vivid color, wide viewing angle, light weight, thin form factor and several other advantages make AMOLEDs very competitive to challenge liquid-crystal display (LCD) technologies.…”