The United States laboratory through magnetic doping technology to improve the efficiency of 30% OLED

The day before, the United States Oak Ridge National Laboratory, ORNL National Laboratory (ORNL) claimed that, through to the OLED doped magnetic nanoparticles, the OLED efficiency is increased by 30%. When the magnetic material is introduced into the OLED, the brightness can be controlled without additional electric contact.

It was found that the efficiency of OLED can be increased by 27% by mixing magnetic nanoparticles into polymer arrays (concentration less than 1/1000). By using the external magnetic field on the doped OLED, the efficiency can be increased by 5%. Therefore, compared with the traditional OLED, the efficiency has been increased by 32%.

When high energy injected electrons and holes recombine, light emission occurs in solid LED, reducing their energy levels and causing a single photon to be emitted to compensate. A LED with 100% efficiency will recombine each injected electron and hole. In the actual device, the efficiency of less than 100%. However, if they are confined to a small area, the design engineer will be able to achieve maximum efficiency as much as possible. ORNL senior researcher Jian Shen said: "what we have done is by doping very low concentrations of magnetic nanoparticles into organic polymers, thereby enhancing the luminous efficiency of OLED. Doping allows us to control the density of OLED with a magnetic field. However, the conventional OLED density is regulated by the electric field, which requires electrical contact. "

When the electron and hole with a pair, before restructuring, they are called elicitors. The magnetic spin of each part of the elicitor is random, resulting in a variable efficiency in the recombination. In order to improve the efficiency of the reorganization, the National Laboratory of cobalt and iron (CoFe) made of magnetic nanoparticles and organic polymer OLED doped together. Because of the presence of magnetic nanoparticles, a large number of excited atoms with reverse spin are accumulated, and the reverse polarity charge carriers are more likely to recombine. Therefore, the magnetic doping OLED is more efficient. Shen said.

The team of the national laboratory will also carry out experiments with different doping levels as well as various methods of mixing magnetic nanoparticles with polymer in order to achieve the same concentration, which can further improve the efficiency of OLED.

OLED panel

Source: Nikkei BP