Double-Heterojunction Nanorod Light-Emitting Diodes with High Efficiencies at High Brightness Using Self-Assembled Monolayers

Yiran Jiang, Nuri Oh, Moonsub Shim

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Size-tunable, narrow-bandwidth emission, low threshold voltage, and high external quantum efficiency (EQE) make quantum dot light-emitting diodes (QD-LEDs) promising in next-generation display and lighting technologies. However, the maximum efficiencies are often observed in a relatively low-current, low-brightness regime, and the efficiency droop leads to less-than-ideal performance at high-luminance conditions useful for many applications. Here, we examine solution-processed, double-heterojunction nanorod (DHNR)-LEDs with self-assembled monolayer (SAM) modified indium tin oxide (ITO) electrodes. The SAMs can modify the surface and the work function of ITO, facilitate hole transport into the device, and therefore improve charge balance in DHNR-LEDs. Extremely bright DHNR-LEDs with maximum luminance over 100 000 cd/m2 are demonstrated. Furthermore, maximum efficiencies appear at high luminance conditions that can be achieved at very low bias and current density (e.g., 3.1 V and 53 mA/cm2 at ∼10 000 cd/m2, corresponding to EQE = 10.7%, current efficiency = 21.7 cd/A, and luminous power efficacy = 19.5 lm/W). Despite the fact that DHNRs have only about half the photoluminescence quantum yield of core/shell QDs, the achieved efficiencies at high luminance conditions are comparable to or surpass those demonstrated by the state-of-the-art QD-LEDs.

Original languageEnglish
Pages (from-to)1862-1868
Number of pages7
JournalACS Photonics
Volume3
Issue number10
DOIs
StatePublished - 2016 Oct 19

Fingerprint

Nanotubes
Self assembled monolayers
Nanorods
nanorods
Light emitting diodes
Heterojunctions
heterojunctions
Luminance
Quantum Dots
brightness
luminance
light emitting diodes
Light
Tin oxides
Quantum efficiency
indium oxides
Indium
tin oxides
Semiconductor quantum dots
quantum efficiency

Keywords

  • charge balance
  • double-heterojunction nanorods
  • high brightness
  • light-emitting diodes
  • self-assembled monolayer

Cite this

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title = "Double-Heterojunction Nanorod Light-Emitting Diodes with High Efficiencies at High Brightness Using Self-Assembled Monolayers",
abstract = "Size-tunable, narrow-bandwidth emission, low threshold voltage, and high external quantum efficiency (EQE) make quantum dot light-emitting diodes (QD-LEDs) promising in next-generation display and lighting technologies. However, the maximum efficiencies are often observed in a relatively low-current, low-brightness regime, and the efficiency droop leads to less-than-ideal performance at high-luminance conditions useful for many applications. Here, we examine solution-processed, double-heterojunction nanorod (DHNR)-LEDs with self-assembled monolayer (SAM) modified indium tin oxide (ITO) electrodes. The SAMs can modify the surface and the work function of ITO, facilitate hole transport into the device, and therefore improve charge balance in DHNR-LEDs. Extremely bright DHNR-LEDs with maximum luminance over 100 000 cd/m2 are demonstrated. Furthermore, maximum efficiencies appear at high luminance conditions that can be achieved at very low bias and current density (e.g., 3.1 V and 53 mA/cm2 at ∼10 000 cd/m2, corresponding to EQE = 10.7{\%}, current efficiency = 21.7 cd/A, and luminous power efficacy = 19.5 lm/W). Despite the fact that DHNRs have only about half the photoluminescence quantum yield of core/shell QDs, the achieved efficiencies at high luminance conditions are comparable to or surpass those demonstrated by the state-of-the-art QD-LEDs.",
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Double-Heterojunction Nanorod Light-Emitting Diodes with High Efficiencies at High Brightness Using Self-Assembled Monolayers. / Jiang, Yiran; Oh, Nuri; Shim, Moonsub.

In: ACS Photonics, Vol. 3, No. 10, 19.10.2016, p. 1862-1868.

Research output: Contribution to journalArticle

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