Recently, Beijing Zaicheng Technology Co., Ltd. (hereinafter referred to as zenith nano Zaicheng Technology) and its co-founder, Professor L. Jay Guo (Lingjie Guo) from the University of Michigan, together with his research team, published the paper Tackling light trapping in organic light-emitting diodes by complete elimination of waveguide modes in the academic journal Science. This work was conducted at the Lurie Nanofabrication Facility of the University of Michigan with the support of zenith nano Zaicheng Technology.
This marks another major achievement of zenithnano Zaicheng Technology in superconducting electrode materials for the OLED field: leveraging zenithnano Zaicheng Technology’s core metamaterials, the luminous efficiency of OLEDs has been greatly improved, delivering innovative solutions for the advancement of the OLED display industry.
Traditional waveguide mode decoupling methods for organic light-emitting diodes (OLEDs) are generally non-scalable and raise manufacturing complexity and costs. The indium-tin-oxide-free transparent anode technology improves efficiency without compromising the performance of other devices. Nevertheless, prior research lacked rigorous analysis.
Chang yeong Jeong, a doctoral candidate in Electrical Engineering and Computer Science, works on ultra-thin-film-based OLEDs in Professor Jay Guo’s laboratory. (Photo: Robert Coulius / Michigan Engineering)The research team adopted an ultra-thin film as the transparent electrode and carried out systematic modal analysis of OLEDs. The team pointed out that waveguide modes can be completely eliminated by designing an OLED structure with a thickness below the waveguide mode cutoff thickness. Refractive index matching fluid and prisms were used to experimentally verify the waveguide modes in organic optical waveguides. The uniform copper-seeded silver thin film features a negative dielectric constant, an ultra-thin thickness (~5 nm) and high electrical conductivity. These properties suppress the formation of waveguide modes and boost the external quantum efficiency without impairing any other characteristics of the OLED.
The research team systematically investigated the optical power distribution of ultra-thin-film-based OLEDs. The paper states that waveguide modes can be fully eliminated by optimizing organic stacks and ultra-thin Ag anodes. According to the publication, this is the first systematic study to demonstrate the complete removal of waveguide modes using thin-film electrode technology through detailed analysis and experiments. This simple yet effective method is compatible with common manufacturing processes and enhances the EQE of OLEDs while keeping other device characteristics intact.
zenithnano Zaicheng Technology was founded in 2018. It is a nano new material R&D and manufacturing enterprise focusing on flexible conductive films. The core product of zenithnano Zaicheng Technology is the flexible nano transparent conductive film, jointly developed by Beijing Collaborative Innovation Research Institute and the University of Michigan (UMich), USA.