TY - JOUR
T1 - Double-Heterojunction Nanorod Light-Emitting Diodes with High Efficiencies at High Brightness Using Self-Assembled Monolayers
AU - Jiang, Yiran
AU - Oh, Nuri
AU - Shim, Moonsub
N1 - Funding Information:
The authors thank Peter Trefonas and Jong Keun Park for helpful discussions. This material is based upon work supported by the Dow Chemical Company and U.S. NSF (Grant No. DMR-1507170). Experiments were carried out in part in the Frederick Seitz Materials Research Laboratory Central Facilities, University of Illinois
Publisher Copyright:
© 2016 American Chemical Society.
PY - 2016/10/19
Y1 - 2016/10/19
N2 - 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.
AB - 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.
KW - charge balance
KW - double-heterojunction nanorods
KW - high brightness
KW - light-emitting diodes
KW - self-assembled monolayer
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U2 - 10.1021/acsphotonics.6b00371
DO - 10.1021/acsphotonics.6b00371
M3 - Article
AN - SCOPUS:84992170433
SN - 2330-4022
VL - 3
SP - 1862
EP - 1868
JO - ACS Photonics
JF - ACS Photonics
IS - 10
ER -