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Research Area

Research Area



Display Devices



Organic Light Emitting Diodes (OLED)


  Color filter-less & shadow maks-less full color OLED








Quantum-Dot Light Emitting Diodes (QD-LED) 



 Colour-tuneable QD-LED

Most colour display devices are composed of R/G/B sub-pixels spatially separated in a 'side-by-side' geometry. This layout of sub-pixels is an essential technology in display devices to reproduce a wide range of colours, but it has clear limitations such as the reductions in resolution and optical efficiency. An innovative approach to overcome these limitations is to implement colour-tuneable pixel technology. We research unique device structures that can reproduce various colours in a single pixel.





   -S. H. Song, S. J. Park, T. J. Bae, K. M. Jung, W. H. Park, Y. S. Kim, Q. Yan, S. S. Kim*, and J. K. Song*, "All-solution-processed colour-tuneable quantum-dot light-emitting diode driven by AC signal", Nanoscale, 12(32), 17020 (2020)



 Performance Improvement

Quantum dot is a promising material, in which bandgap depends on its size. It emits highly pure color, which is one of the most important factors in display devices. However, it remains several critical drawbacks such as quantum efficiency and lifetime. We research new device structures, materials, and fabrication process that can improve the efficiency and lifetime of QD-LED.





   -D. H. Song, S. H. Song, T. Z. Shen, J. S. Lee, W. H. Park, J. M. Kim, Y. S. Kim, W. J. Yu, S. S. Kim*, and J. K. Song*, "Reduced Graphene Oxide as Efficient Hole Injection Layer for Quantum-Dot Light-Emitting Diodes", Physica Status Solidi A, 215(23), 1800517 (2018)






Photonic Devices 




2D Materials



 Liquid crystal of 2D materials

Graphene Oxides (GO) have an extremely high Kerr coefficient, and one can control the GO alignment with extremely low electric fields. Using this property, we aim to develop an extremely low power display device using graphene-oxide dispersions.





  -T. Z. Shen, S. H. Hong, and J. K. Song *, “Electro-optical switching of graphene-oxide liquid crystals with an extremely large Kerr coefficient” , Nature Materials, 13 394-399 (2014)



 Photonic crystal of 2D materials

A few lyotropic 2D materials exhibits Bragg reflection due to periodic arrangement within solvent. By controlling the 2D material concentration and alignment, one can obtain colorful drawings.





  -T. Z. Shen, S. H. Hong, B. Lee and J. K. Song*, "Bottom-up and top-down manipulations for multi-order photonic crystallinity in a graphene-oxide colloid.", NPG Asia Materials, 8, e296 (2016)