Stretchable array of CdSe/ZnS quantum-dot light emitting diodes for visual display of bio-signals

Yonghui Lee, Dong Sik Kim, Sang Woo Jin, Hanchan Lee, Yu Ra Jeong, Ilhwan You, Goangseup Zi, Jeong Sook Ha

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Display devices that can visually present various bio-signals are a core future technology required for skin attachable wearable electronics. Quantum dot light emitting diodes (QD-LEDs), which can be used as high performance display devices, exhibit many advantages such as a narrow bandwidth, high color purity, high environmental stability, easy and fast processing, and a high brightness at low voltage. In this study, we report on the fabrication of a stretchable QD-LED array for the visual display of body movement and skin temperature signals from skin-attached sensors. After forming an array of a rigid NOA63 islands, an array of CdSe/ZnS QD-LEDs is fabricated on top of that island array and electrically connected using liquid metal Galinstan interconnections. Finally, the array of QD-LEDs on the NOA63 islands is transferred onto a stretchable elastomer substrate of Ecoflex/PDMS. Of particular importance, for stable performance of the QD-LEDs under deformation, in replacement of the conventionally used ITO, a flexible and highly transparent electrode of Au grid/Ethylene glycol doped PEDOT:PSS is used. Such a design architecture can minimize the strain applied to the QD-LEDs by concentrating the strain onto the soft elastomer film substrate and the Galinstan interconnections. As a result, the fabricated QD-LED array exhibits stable operation under both 50% uniaxial and 30% biaxial strains. After attachment of the stretchable QD-LED array onto skin, the extent of knee bending, and changes in skin temperature are displayed as changes in the pattern of the QD-LED array. This work demonstrates the potential application of our stretchable array of QD-LEDs for easy and daily monitoring of health conditions through a visual display.

Original languageEnglish
Article number130858
JournalChemical Engineering Journal
Volume427
DOIs
Publication statusPublished - 2021 Jan 1

Keywords

  • Bio-signals
  • Body movement
  • Liquid metal
  • QD-LED
  • Skin temperature
  • Stretchable display

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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