Merck, the cutting-edge material developer from Germany, said Thursday the company has started mass production of hole transport materials for organic light-emitting diode displays used in smartphones.

Better known as HTM, the material is applied to common layers of OLED panels, and helps improve the efficiency and lifespan of panels, the company said.

Merck, which has been supplying the material for Korea’s largest OLED panel maker LG Display for large-size displays, will expand its reach to also provide the material for mobile devices sporting OLED screens, it said.

The materials produced by Merck are expected to be used in LG Display products planned for commercial launch in 2021.

According to data from market researcher Display Supply Chain Consultants, the number of flexible OLED panels produced by LG Display for smartphones was 31.7 million units in 2020 -- a sharp increase from 9.7 million units in 2019. This is expected to increase further to 52.7 million units this year.

“Since Merck opened the Korea OLED R&D center in 2011, the R&D facilities, manpower and OLED production facility have been continuously reinforced to provide short-distance services to Korean panel makers and make it possible to respond quickly to the highest quality materials produced in Korea,” said Kim Woo-kyu, managing director of Merck Korea.

“The expanded application of this material has laid the foundation for even closer cooperation with Korean OLED panel makers in the future.”

Merck started its OLED and organic materials businesses in 2005, opened a research center for OLED synthesis and material development in 2011 and opened an OLED application center in 2014. In 2020, Merck announced the investment of an additional 25 billion won ($21.75 million) to establish a next-generation OLED materials manufacturing facility at the Poseung National Industrial Complex in Pyeongtaek, Gyeonggi Province.