All-solution processed, multilayer, and inverted quantum-dot light-emitting diodes (QD-LEDs) are developed in this work. To protect the QDs from dissolving by the solvents of upper layers, the solvents of poly(9-vinlycarbazole) (PVK) hole transporting layer are first investigated. The QD layer has been less affected by o-dichlorobenzene solvent than other typical solvents like chloroform and chlorobenzene. Second, to deposit a hydrophilic poly(ethylenedioxythiophene)/polystyrenesulfonate (
Pedot: PSS) hole injection layer on top of hydrophobic PVK, the surface energy of the
Pedot: PSS is reduced by using isopropanol as the additive. With optimized conditions, the demonstrated QD-LEDs exhibit a maximum luminance of 16290 cd/m(2) and a peak current efficiency of 4.1 cd/A, which is the highest among the reported values. These results may offer a practicable platform for further research, leading to the achievement of all-solution processed, multilayer, and efficient inverted QD-LEDs.
Keywords: all-solution-processed; intermixing; inverted QD-LEDs; light-emitting diodes; orthogonal solvents; quantum dots.