Utilizing a compact diamino-based ligand as a charge balancer in quantum dot light-emitting diodes.

Charge imbalance within the emissive layer (EML) has been identified as a major obstacle to achieving high-performance quantum dot light-emitting diodes (QD-LEDs). To address this issue, we propose the use of a compact diamino-based ligand as a universal approach to improve the charge balance within the QD EML. Specifically, we treat QDs symmetrically with 1,4-diaminobutane (DAB) on both the bottom and top sides. This treatment simultaneously modulates the injection properties of electrons and holes, effectively suppressing electron injection into QDs while facilitating hole injection. As a result, QD-LEDs with symmetrical DAB treatment exhibit a 1.5-fold increase in external quantum efficiency and a remarkable 4.5-fold increase in device lifetime. These results highlight the role of the compact diamine-based ligands as highly efficient charge balancers to realize high-performance and highly stable QD-LEDs.

Recent Progress on Quantum Dot Patterning Technologies for Commercialization of QD-LEDs: Current Status, Future Prospects, and Exploratory Approaches.

Colloidal quantum dots (QDs) are widely regarded as advanced emissive materials with significant potential for display applications owing to their excellent optical properties such as high color purity, near-unity photoluminescence quantum yield, and size-tunable emission color. Building upon these attractive attributes, QDs have successfully garnered attention in the display market as down-conversion luminophores and now venturing into the realm of self-emissive displays, exemplified by QD light-emitting diodes (QD-LEDs). However, despite these advancements, there remains a relatively limited body of research on QD patterning technologies, which are crucial prerequisites for the successful commercialization of QD-LEDs. Thus, in this review, an overview of the current status and prospects of QD patterning technologies to accelerate the commercialization of QD-LEDs is provided. Within this review, a comprehensive investigation of three prevailing patterning methods: optical lithography, transfer printing, and inkjet printing are conducted. Furthermore, several exploratory QD patterning techniques that offer distinct advantages are introduced. This study not only paves the way for successful commercialization but also extends the potential application of QD-LEDs into uncharted frontiers.