Korean materials company is expected to mass-produce blue phosphorescent OLED materials this year

On February 17, South Korean OLED materials company Lordin stated at the "Korea-India OLED Innovation Forum" held in Hyderabad, Telangana, India, that it will mass-produce blue phosphorescent OLED materials this year.

OLEDs are made of materials that can emit their own light. According to the different ways of emitting light, OLED can be divided into "phosphorescent" type and "fluorescent" type. The luminous efficiency of fluorescent OLED is 25%, while the luminous efficiency of phosphorescent OLED can reach 100%. However, the stability of phosphorescence is lower than that of fluorescence, making it difficult to achieve perfection. Among the three primary colors of red, green and blue, red and green phosphorescent OLEDs have been commercialized, but blue has a short lifespan and is difficult to apply to actual panels.

Director of the Lordin Institute said: "In fluorescent structures, three-quarters of the energy is lost in the form of heat, and heat generation will directly lead to shortened lifespan."

In OLEDs, electrons and holes meet and emit light in the light-emitting layer between the anode and cathode. Among them, the excitons in the combined state of electrons and holes play a key role. Depending on the spin combination of electrons and holes, singlet and triplet states will be formed in a ratio of 1:3. Existing fluorescent materials can only convert singlet states into light energy, and the remaining 75% is lost in the form of heat.

In phosphorescence, even the triplet state is used to emit light, which can theoretically achieve 100% internal efficiency. This means it can be brighter at the same current, or achieve the same brightness with lower power consumption. Lordin said: "If the efficiency is increased from 25% to 100%, under the same current benchmark, the brightness can be increased to 4 times, and the power consumption is expected to be reduced by at least 25~50%." This is expected to have direct effects such as extending smartphone battery life, enabling high-brightness HDR on TVs, and improving outdoor visibility.

The basis for blue phosphorescence research and development is thermal stability. The material must be able to withstand the heat of the continuous process for at least one week and maintain the same properties as during the initial stages of deposition. Lordin emphasized: "Before pursuing efficiency, we must first ensure basics such as thermal stability." Lordin focuses on enhancing the stability of the molecular structure. Through deuterium substitution technology, carbon-hydrogen bonds are converted into carbon-deuterium bonds, which can reduce molecular vibration energy and thereby slow down the decomposition rate. "Deuteration plays an integral role in increasing the lifetime of blue materials," Lordin noted.

At the same time, process simplification strategies are also being actively promoted. Typically, a multi-component structure is used, such as an N-type matrix, a P-type matrix and dopants. Lordin proposed the "ZETPLEX" structure that combines a specific host with a dopant. The idea is to reduce the variables in the evaporation process by reducing the number of components, making process control easier. Lordin emphasized: "Simplifying the structure will help ensure uniformity in the mass production stage, and stability and driving voltage characteristics are also being improved."

Lordin said that it has entered the final stage in terms of efficiency, lifespan and driving voltage. In particular, the lifespan has been significantly improved compared to the initial stage, and there is still room for further improvement. "We are optimizing materials and device structures at the same time, with the goal of going beyond R&D to actual mass production and application this year," said the director of the Lordin Institute.

If blue phosphorescence is put into mass production, it is expected that the revenue structure of the OLED industry will also change. Reducing power consumption at the same brightness will affect the cost structure of the panel, while reducing heat generation will help extend panel life and improve reliability. Its application range is also quite wide, covering IT OLED, large TVs and next-generation extended reality devices. The industry believes that once blue phosphorescence technology matures, OLED will usher in another generational change.

Although OLED has surpassed LCD in terms of picture quality competitiveness, there is still room for improvement in terms of power consumption efficiency, lifespan and manufacturing stability. Lordin said: "Blue phosphorescence is not a choice, but a necessary stage. The application of this technology will open the next decade of OLED."