Efficient Quantum Dot Light-emitting Diodes Research Articles

Stable and efficient quantum-dot light-emitting diodes based on solution-processed multilayer structures

Researchers demonstrate solution-processed light-emitting diodes based on a quantum-dot emissive layer between an organic hole-transport layer and an electron-transport layer of ZnO nanoparticles. The device achieves a luminance of 68,000 cd m−2 and power efficiencies of up to 8.2 lm W−1.

Highly Efficient Quantum-Dot Light-Emitting Diodes with DNA−CTMA as a Combined Hole-Transporting and Electron-Blocking Layer

Owing to their narrow bright emission band, broad size-tunable emission wavelength, superior photostability, and excellent flexible-substrate compatibility, light-emitting diodes based on quantum dots (QD-LEDs) are currently under intensive research and development for multiple consumer applications including flat-panel displays and flat lighting. However, their commercialization is still precluded by the slow development to date of efficient QD-LEDs as even the highest reported efficiency of 2.0% cannot favorably compete with their organic counterparts. Here, we report QD-LEDs with a record high efficiency (approximately 4%), high brightness (approximately 6580 cd/m(2)), low turn-on voltage (approximately 2.6 V), and significantly improved color purity by simply using deoxyribonucleic acid (DNA) complexed with cetyltrimetylammonium (CTMA) (DNA-CTMA) as a combined hole transporting and electron-blocking layer (HTL/EBL). This, together with controlled thermal decomposition of ligand molecules from the QD shell, represents a novel combined, but simple and very effective, approach toward the development of highly efficient QD-LEDs with a high color purity.