Researchers introduce heterostructure based metal oxide charge transfer complex for displays

By Lim Chang-won Posted : January 19, 2022, 15:51 Updated : January 19, 2022, 15:52

[Courtesy of the Korea Advanced Institute of Science and Technology]

SEOUL -- Metal oxide thin films are considered an attractive material for various functional applications because of their favorable energy band structure, excellent processability, and high stability. Metal oxides are intensively used for multilayered optoelectronic devices such as organic light-emitting diodes and quantum-dot light-emitting diodes for ensuring efficient charge transport and charge injection into the emission layer.

Many approaches have been explored to improve device performance by engineering electrical properties, but conventional methods cannot enable both energy level manipulation and conductivity enhancement for achieving optimum energy band configurations.

Researchers from South Korea's two state-run research bodies -- the Advanced Institute of Science and Technology (KAIST) and the Electronics and Telecommunications Research Institute (ETRI) -- have introduced a heterostructure based metal oxide charge transfer complex composed of two complementary metal oxides to simultaneously modulate energy levels and enhance the electrical conductivity of a metal oxide system. 

"This technology will contribute to the implementation of state-of-the-art displays essential for realistic metaverse by innovating how to control the performance of core materials," Jung Yeon-sik, a KAIST professor of materials science and engineering, said in a statement on January 19.

The new charge-transfer complex composed of molybdenum trioxide (MoO3) domains embedded in nickel oxide (NiO) matrices achieved 189 percent improved current efficiency compared to that of MoO3-based green OLEDs and an external quantum efficiency of 17 percent when applied to blue OLEDs, the research team said in a research paper published on the website of Nature Communications, a peer-reviewed, open access, scientific journal. 

"Our strategy overcomes the limitations of conventional metal oxide enhancement methods by delocalizing charge transfer from the surface to the entire film, suggesting an alternative direction for applying metal oxide heterostructures to enhance the performance of multi-layered optoelectronic devices to a great extent," the research team said.
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