Department of Chemical and Biomolecular Engineering
Korea Advanced Institute of Science and Technology

About the Lab

Organic Opto-Electronic Materials Laboratory

■ Large Area Self-Assembly of Liquid Crystal & Supramolecules

  As soft materials, liquid crystal (LC) and supramolecular dendrimers are self-assembling building blocks having numerous merits such as the ability to form a very small feature size (sub-10nm), various ordered phases, diversity in chemical functionality, and rapid construction of nano-structure with high ordering. The application areas of liquid crystals and supramolecules are optoelectronic materials, particle trapping, 3D microlens array, selective membranes, and novel nano-lithographic templates. Our group proceeds in-depth studies for supramolecules and liquid crystal self-assembly for nano-fabrication and try to use them in practical applications.

 

■ Liquid Crystal Alignment for LCD, Photolithography Application

 


Liquid crystal displays are used mostly in applications such as cellular phones, wall-mounted flat panels and laptop PCs. Alignment technique is one of the key techniques for LCDs. The conventional alignment method is the rubbing method, which is mechanical rubbing of polymer film on a transparent electrode. For alternatives to the rubbing process, noncontact methods such as photo-alignment have been used, but it has some critical drawbacks. In our group, various nano patterns were fabricated and used to align various liquid crystals. Recently, disclination line removal has been achieved through control of physical geometry. Also, lyotropic liquid crystals have been applied to LC polarizers, and commercial liquid crystal technology will be advanced to be used to next generation LCDs.

 

■ High Resolution Nano-Patterning

  Lithographic techniques may be divided into top-down and bottom-up methods. Top-down methods are generally represented as conventional lithographic techniques in semiconductor industry using photo masks. Bottom-up methods use molecular self-assembly to obtain regularly ordered structure and their resolution is defined by molecular nanostructures in 1~100 nm range. Nowadays, the development of high resolution nanostructure with various shapes is required for high performance and various applications in optic and electronic devices. We are developing new lithographic techniques based on top-down approach and bottom-up approach or fusion of those for realization of high performance device in nanotechnology.

 


 

■ Electronic Sensing Devices

Liquid crystal displays are used mostly in applications such as cellular phones, wall-mounted flat panels and laptop PCs. Alignment technique is one of the key techniques for LCDs. The conventional alignment method is the rubbing method, which is mechanical rubbing of polymer film on a transparent electrode. For alternatives to the rubbing process, noncontact methods such as photo-alignment 

have been used, but it has some critical drawbacks. In our group, various nano patterns were fabricated and used to align various liquid crystals. Recently, disclination line removal has been achieved through control of physical geometry. Also, lyotropic liquid crystals have been applied to LC polarizers, and commercial liquid crystal technology will be advanced to be used to next generation LCDs.Development of a high-performance gas sensor is essential in human life due to its major role in the field of personal safety, public security, medical diagnosis, detection of environmental toxins, and many more. We are investigating the chemiresistive type of gas sensor, which is a highly sensitive, rapid, reversible and repeatable sensing device. The chemiresistor development in this study aims to detect volatile organic compounds (VOCs) with high sensitivity, selectivity and stability with the potential to be used in promising applications in breath analysis for lung cancer diagnosis. 

 

■ Transparent Electrodes

Transparent and electrically conductive films have a variety of fast-growing applications ranging from window glass to flat-panel displays. Also, transparent conductors are an essential component in many optoelectronic devices. In our research group, various materials such as graphene, carbon nanotube, metal nanowire and metal mesh have been investigated to develop transparent electrodes with high performance. Especially, we are trying to understand the critical factors affecting the domain structure of graphene by observing the graphene domains through aligned liquid crystals on the surface of graphene.  


 

■ Electronic Sensing Devices

Beyond the capture and storage of CO2, we will further develop a CO2 conversion technology by using sustainable light energy to reduce the CO2 concentration and convert them to energy sources such as methane, methanol and ethanol. Photocatalysts are the key materials to conduct CO2 decomposition by absorbing sunlight and generating energetic electrons and holes. However, the photoconversion of CO2 remains a challenge due to the low efficiency of 

photocatalysts, uncertain mechanism of CO2 photoconversion, stable chemical state of CO2 and complex multi-electron reaction. In our group, we are focusing on developing a highly efficient CO2 photoconversion system with high selectivity through materials with controlled structures in nano-scale. 

 

 

 

Hee Tae Jung (정희태) 
KAIST Chair, Professor


Office Phone: +82-42-350-3931
Fax: +82-42-350-3910
E-mail: heetae@kaist.ac.kr
Homepage: http://ooem.kaist.ac.kr

 

0

추천하기

0

반대하기

ProfessorHee Tae Jung

Hits1,745

  • 페이스북 공유
  • 트위터 공유
  • Google+ 공유
  • 인쇄하기