Hole-Injection-Barrier Effect on the Degradation of Blue Quantum-Dot Light-Emitting Diodes.
ACS Nano
; 2024 Feb 08.
Article
in En
| MEDLINE
| ID: mdl-38329720
ABSTRACT
Inefficient hole injection presents a major challenge in achieving stable and commercially viable solution-processed blue electroluminescent devices. Here, we conduct an in-depth study on quantum-dot light-emitting diodes (QLEDs) to understand how the energy levels of common electrodes and hole-transporting layers (HTL) affect device degradation. Our experimental findings reveal a design rule that may seem nonintuitive combining an electrode and HTL with matched energy levels is most effective in preventing voltage rise and irreversible luminance decay, even though it causes a significant energy offset between the HTL and emissive quantum dots. Using an iterative electrostatic model, we discover that the positive outcomes, including a T95 lifetime of 109 h (luminance = 1000 nits, CIE-y = 0.087), are due to the enhanced p-type doping in the HTL rather than the assumed reduction in barrier heights. Furthermore, our modified hole injection dynamics theory, which considers distributed density-of-states, shows that the increased HTL/quantum-dot energy offset is not a primary concern because the effective barrier height is significantly lower than conventionally assumed. Following this design rule, we expect device stability to be enhanced considerably.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Type of study:
Prognostic_studies
Language:
En
Journal:
ACS Nano
/
ACS nano
Year:
2024
Document type:
Article
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