Highly Efficient and Bright Inverted Top-Emitting InP Quantum Dot Light-Emitting Diodes Introducing a Hole-Suppressing Interlayer

Taesoo Lee; Donghyo Hahm; Kyunghwan Kim; Wan Ki Bae; Changhee Lee; Jeonghun Kwak

doi:10.1002/smll.201905162

Highly Efficient and Bright Inverted Top-Emitting InP Quantum Dot Light-Emitting Diodes Introducing a Hole-Suppressing Interlayer

Small. 2019 Dec;15(50):e1905162. doi: 10.1002/smll.201905162. Epub 2019 Nov 14.

Authors

Taesoo Lee¹, Donghyo Hahm², Kyunghwan Kim¹, Wan Ki Bae³, Changhee Lee¹, Jeonghun Kwak¹

Affiliations

¹ Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Seoul National University, Seoul, 08826, Republic of Korea.
² School of Chemical and Biological Engineering, The National Creative Research Initiative Center for Intelligent Hybrids, Seoul National University, Seoul, 08826, Republic of Korea.
³ Sungkyunkwan Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, Gyeonggi-do, 16419, Republic of Korea.

PMID: 31729177
DOI: 10.1002/smll.201905162

Abstract

InP quantum dots (QDs) based light-emitting diodes (QLEDs) are considered as one of the most promising candidates as a substitute for the environmentally toxic Cd-based QLEDs for future displays. However, the device architecture of InP QLEDs is almost the same as the Cd-based QLEDs even though the properties of Cd-based and InP-based QDs are quite different in their energy levels and shapes. Thus, it is highly required to develop a proper device structure for InP-based QLEDs to improve the efficiency and stability. In this work, efficient, bright, and stable InP/ZnSeS QLEDs based on an inverted top emission QLED (ITQLED) structure by newly introducing a "hole-suppressing interlayer" are demonstrated. The green-emitting ITQLEDs with the hole-suppressing interlayer exhibit a maximum current efficiency of 15.1-21.6 cd A^-1 and the maximum luminance of 17 400-38 800 cd m^-2 , which outperform the recently reported InP-based QLEDs. The operational lifetime is also increased when the hole-suppressing interlayer is adopted. These superb QLED performances originate not only from the enhanced light-outcoupling by the top emission structure but also from the improved electron-hole balance by introducing a hole-suppressing interlayer which can control the hole injection into QDs.

Keywords: efficiency; hole suppressing interlayer; indium phosphide; quantum dot-based light emitting diodes (QLEDs); top emitting structure.

Abstract

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