Lifetime elongation of quantum-dot light-emitting diodes by inhibiting the degradation of hole transport layer
Open Access
- 11 June 2021
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in RSC Advances
- Vol. 11 (34), 20884-20891
- https://doi.org/10.1039/d1ra03310g
Abstract
Developing a colloidal quantum-dot light-emitting device (QDLED) with high efficiency and good reliability is necessarily preliminary for the next-generation high-quality display application. Most QDLED reports are focused on efficiency improvement, but the device operational lifetime issue is less addressed and also the relevant degradation mechanisms. This study achieved a 1.72 times elongation in the operational lifetime and a 9 times improvement in the efficiency of QDLED by inserting a hole-transporting/electron-blocking poly(9-vinylcarbazole) (PVK) layer, which prevented operational degradation on poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-(N-(4-secbutylphenyl))-diphenylamine)] (TFB) hole-transporting layer and also confined the electron in the QD-emitting layer. Although the TFB/PVK HTL structure is a well-known pair to enhance the device performance, its detailed mechanisms were rarely mentioned, especially for relative operational lifetime issues. Herein, a new insight behind operational lifetime elongation of QDLED is disclosed through various fundamental experiments including steady-state photoluminescence, transient electroluminescence and single-carrier only devices. Evidently, other than QD degradation, this study found that the other crucial factor that decreased the device lifetime was TFB-HTL degradation using steady-state photoluminescence and transient electroluminescence analyses. The PVK electron-only device exhibited a stable voltage value when it was driven by fixed current, which also affirmed that PVK has excellent electron-stability characteristics.Funding Information
- H2020 Marie Skłodowska-Curie Actions (823720)
- Ministry of Science and Technology, Taiwan (MOST 109-2622-E-155-014, 108-2221-E-155-051-MY3, 108-2912-I-155-504, 108-2811-E-155-504, 107-2221-E-155-058-MY3, 107-2221-E-002-156-MY3, 107-2221-E-155-027, 107-3113-E-155-001-CC2, 106-3113-E-155-001-CC2, 106-2221-E-155-036, 106-2923-E-155-002-MY3, 106-2923-E-002-004-MY3, 105-2221-E-002-130-MY3)
This publication has 48 references indexed in Scilit:
- Organic light-emitting diodes under high currents explored by transient electroluminescence on the nanosecond scalePhysical Review B, 2011
- Dependence of the stability of organic light-emitting diodes on driving modeChinese Science Bulletin, 2011
- Tandem colloidal quantum dot solar cells employing a graded recombination layerNature Photonics, 2011
- Verification of the dispersive charge transport in a hydrazone:polycarbonate molecularly doped polymerJournal of Physics: Condensed Matter, 2009
- Nondispersive hole transport in a polyfluorene copolymer with a mobility of 0.01cm2V−1s−1Applied Physics Letters, 2006
- Charge carrier transport in polyvinylcarbazoleJournal of Physics: Condensed Matter, 2006
- A dynamic model for injection and transport of charge carriers in pulsed organic light-emitting diodesSemiconductor Science and Technology, 2004
- Spontaneous and reverse-bias induced recovery behavior in organic electroluminescent diodesApplied Physics Letters, 1998
- Light-emitting diodes made from cadmium selenide nanocrystals and a semiconducting polymerNature, 1994
- Dispersive nature of hole transport in polyvinylcarbazolePhysical Review B, 1989