2008 IDW look at the latest developments in OLED Technology

2008 IDW (International Display Workshops) in December 3, 2008 to 5, in Niigata County, Japan (Niigata City) Toki Messe Convention Center The Institute of held by Image Information and TELevision Engineers (ITE) and The Society for Information Display (SID) of the host, is the last event display related industries at the end of the year. A number of manufacturers and the relevant materials display manufacturers to announce its latest technology, academic circles to publish their research results. This seminar is divided into 15 themes (Table 1), OLED is a sub seminar which, in addition, other items in the seminar also have OLED, such as Active Matrix Displays and Flexible Displays. In this paper, the development trend and trend of the OLED industry in the papers of the major manufacturers and academic circles are reviewed, and a brief introduction is made on the latest development of OLED related materials, components and processes.

The Sony launched the world's first mass production of OLED TV XEL-1 in 2007, has injected a booster for the market, the development of the OLED race began warming, however the second half of 2008 after the outbreak of the global financial tsunami, global consumption greatly reduced, LCD industry faces the hitherto unknown challenge, not natural and OLED industry in addition to the development of competition spared, to speed up the pace, but also one of the important key cost down speed. For each material manufacturers for the latest research results of OLED related materials as well as panel manufacturers of the latest production technology, are described as follows.

(1) New singlet blue and green emitters for OLED applications Germany Merck --- Merck, company released their OLED fluorescent material, introduced the blue sky (sky blue), blue (deep blue) and green (green) materials.

(2) Novel Host Material Based on Benzodifuran with Ambipolar Charge Transport Properties - Tokyo University, Japan University of Tokyo published structures such as light emitting materials CZBDF shown in Figure 1, Tg point is 162 DEG C, good thermal stability, LUMO eV = 2.47, HOMO = 5.79 eV. It is important that the main luminescent material has the properties of ambipolar, and it can be seen from figure two that the transmission speed of electrons and holes in ~10-3 is very high.

Figure 1. The structure of the main luminescent material CZBDF

(3) Systematic Development of Soluble OLED Materials at Merck Merck, OLED Germany soluble component structure materials of Merck are ITO /PEDOTPSS / HIL / LEP / Ba / Al. The addition of a certain percentage of monomers in the blue light component can significantly increase the lifetime of the component without changing the color purity of the light, as shown in figure two. Further control of the molecular weight of the size of 450000 g/mol or more, can increase the life of the component to 1200 hours (1000nits).

Figure two. The relationship between the lifetime and the brightness of the soluble blue OLED

(4) 102 lm/W White Phosphorescent OLED USA UDC - UDC, published two white OLED components, the luminous efficiency were 89 lm/W and 102 lm/W, breaking the world record, a detailed material and impressiveness, but did not reveal the component structure. These two white light components WOLED-1 and WOLED-2 coordinates are (0.41, 0.46) and (0.48, 0.46), color temperature is 3900K and 2800K, the EL spectrum as shown in figure three.

Figure three. EL spectra of white light components

(5) Horizontal Dipping Method for Simple Fabricating OLEDs - Kwangwoon University Korea method, a new solution-process is proposed, named Horizontal Dipping (H-dipping), figure four is the schematic diagram by the control cylinder and substrate distance (H), and the moving speed of the substrate (V), can control the organic luminous film accurate thickness and uniformity of the components, structure of ITO / PEDOT:PSS / EL layer / CsF / Al, such as the relationship between figure five for the moving speed and film thickness. On the substrate of 10cm x 10 cm, the film with high uniformity can be obtained by H-dipping method, and the average roughness (roughness) is only 0.897 nm.

Figure four, H-dipping schematic

Fig. five the relationship between film thickness and substrate moving speed