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

On February 17th, South Korean OLED material company Lordin announced 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 composed of materials capable of emitting light by themselves. Depending on the method of light emission, OLEDs can be divided into "phosphorescent" and "fluorescent" types. The luminous efficiency of fluorescent OLEDs is 25%, while that of phosphorescent OLEDs can reach 100%. However, the stability of phosphorescence is lower than that of fluorescence, making it difficult to achieve perfectly. Among the three primary colors (RGB) of red, green, and blue, red and green phosphorescent OLEDs have been commercialized, but blue (which consumes the most energy) has a shorter lifespan, making it difficult to apply to actual panels.

The director of the Lordin Institute stated, "In the fluorescent structure, three-quarters of the energy is dissipated in the form of heat, which directly leads to a shortened lifespan.".

In OLEDs, electrons and holes meet and emit light in the emissive layer (EML) situated between the anode and cathode. Among them, excitons, which are bound states of electrons and holes, play a pivotal role. Depending on the spin configuration of electrons and holes, singlet and triplet states are formed in a 1:3 ratio. Current fluorescent materials can only convert singlet states (25%) into light energy, with the remaining 75% dissipated as heat.

Phosphorescence, on the other hand, utilizes even the triplet state for luminescence, theoretically achieving 100% internal efficiency. This means that it can be brighter under the same current, or achieve the same brightness with lower power consumption. Lordin stated, "If the efficiency is increased from 25% to 100%, the brightness can be increased by four times under the same current benchmark, and the power consumption is expected to decrease by at least 25-50%." It is expected to bring direct benefits such as extending the battery life of smartphones, achieving high-brightness HDR for televisions, and improving outdoor visibility.

The foundation of blue phosphorescence research and development lies in thermal stability. The material must withstand the heat from continuous processing for at least a week and maintain the same performance as in the initial stage of deposition. Lordin emphasized, "Before pursuing efficiency, it is essential to first ensure fundamentals 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 vibrational energy and thus slow down the decomposition rate. Lordin pointed out, "Deuteration plays an indispensable role in extending the lifespan of blue materials.".

Meanwhile, the strategy of process simplification is also being actively promoted. Typically, multi-component structures, such as N-type substrates, P-type substrates, and dopants, are employed. Lordin proposed the "ZETPLEX" structure, which combines a specific host with dopants. The idea is to reduce variables during the evaporation process by reducing the number of components, making process control easier. Lordin emphasized: "Simplified structures are conducive to ensuring uniformity during mass production, and stability and driving voltage characteristics are also improving.".

Lordin stated that the current stage involves finalizing improvements in efficiency, lifespan, and driving voltage, with notable enhancements in lifespan compared to the initial stage, and there is still room for further improvement. The director of the Lordin Research Institute said, "We are simultaneously optimizing materials and device structures, with the goal of surpassing research and development and achieving actual mass production and application this year.".

If blue phosphorescence is put into mass production, it is expected that the revenue structure of the OLED industry will also undergo changes. Reducing power consumption at the same brightness level will affect the cost structure of panels, while reduced heat generation will help extend panel lifespan and improve reliability. Its application range is also quite extensive, covering IT OLED, large-screen televisions, and next-generation extended reality devices. The industry believes that once blue phosphorescence technology matures, OLED will usher in another generation replacement.

Although OLED has surpassed LCD in terms of image quality competitiveness, there is still room for improvement in terms of power efficiency, lifespan, and manufacturing stability. Lordin stated, "Blue phosphorescence is not an option, but a necessary stage. The application of this technology will usher in the next decade of OLED.".