Journal of the Microelectronics and Packaging Society (마이크로전자및패키징학회지)

The Korean Microelectronics and Packaging Society (한국마이크로전자및패키징학회)
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A Comparison Study on Various Quantum Dots Light Emitting Diodes Using TiO2 Nanoparticles as Inorganic Electron Transport Layer

무기 전자 수송층으로 TiO2 나노입자를 사용한 다양한 양자점 전계발광 소자의 특성 비교 연구

  • Kim, Moonbon (Department of Advanced Materials Engineering, Kyonggi University) ;
  • Yoon, Changgi (Department of Advanced Materials Engineering, Kyonggi University) ;
  • Kim, Jiwan (Department of Advanced Materials Engineering, Kyonggi University)
  • 김문본 (경기대학교 신소재공학과) ;
  • 윤창기 (경기대학교 신소재공학과) ;
  • 김지완 (경기대학교 신소재공학과)
  • Received : 2019.09.02
  • Accepted : 2019.09.27
  • Published : 2019.09.30
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Abstract

In this study, we fabricated two standard and inverted quantum dot light emitting diodes (QLEDs) using $TiO_2$ nanoparticles (NPs) with lower electron mobility than ZnO NPs as inorganic electron transport layer to suppress electron injection into the emitting layer. Current density was much higher for the inverted QLEDs than the standard ones. The inverted QLEDs were brighter, but showed low current efficiency due to the high current density. In addition, as the current density was higher, the driving voltage was higher, and the red shift was confirmed in the emission wavelength spectrum. The low current density in the standard structured devices showed that the possibility that $TiO_2$ NPs could suppress the electron injection in the QLEDs.

본 연구는 발광층으로의 전자 주입을 억제하기 위해 ZnO 나노입자보다 낮은 전자 이동도를 갖는 $TiO_2$ 나노입자를 무기 전자 수송층으로 사용하여 standard와 inverted 두 가지 구조의 양자점 전계발광 소자를 제작하고 그 특성을 비교하였다. Standard 구조의 소자에서는 전류 밀도가 낮은 것에 비해 inverted 구조의 소자에서는 전류 밀도가 매우 높은 것을 확인하였다. 휘도의 경우 inverted 구조의 소자가 standard 구조의 소자보다 더 높았지만 높은 전류 밀도로 인해 낮은 전류 효율을 나타냈다. 또한 전류 밀도가 높은 만큼 구동 전압이 높았으며, 방출 파장 스펙트럼에서 적색 편이를 확인하였다. Standard 구조의 소자에서 나타난 낮은 전류 밀도를 통해, $TiO_2$ 나노입자가 양자점 전계발광 소자에서 전자 주입을 억제할 수 있는 가능성을 확인하였다.

Keywords

References

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