Transient overshoot and storage of charge carriers on ligands in quantum dot LEDs
Christian Blauth, Paul Mulvaney, Tadahiko Hirai
JOURNAL OF APPLIED PHYSICS | AMER INST PHYSICS | Published : 2019
Quantum dot light emitting diodes (QLEDs) emitting at 410 nm were studied by time-resolved electroluminescence measurements. A transient overshoot after voltage turn-off was seen, which is attributed to the accumulation and storage of charge carriers at the ligand-quantum dot interface. Shorter ligands showed a faster rise time and prevented the formation of an overshoot, whereas longer ligands caused the storage of charges, responded slower, and showed an overshoot. When the external voltage was switched off, the electric field between the injected and stored electrons and holes led to the occurrence of the overshoot. Applying a dual voltage pulse avoided this overshoot and instead a delaye..View full abstract
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Awarded by ARC
The authors thank the ARC for support through Grant No. CE170100026 and Anthony Chesman for valuable discussions.