In-situ repairing quantum-dot-monolayer-film defects for laminated light-emitting diodes

Abstract

Quantum dot (QD) light-emitting diodes (QLEDs) have become one of the primary development directions for next-generation display techniques due to their excellent optoelectronic and solution-processing properties. High-performance QLEDs rely on high-quality light-emitting layers that are mainly stacked QD films deposited by spin-coating (SC). However, preparing large-area and defect-free monolayer films, which is crucial for high-quality displays, is the inherent drawback of the SC technique and is still challenging. Herein, we propose an in-situ defect-repairing strategy to create defect-passivating monolayer QD films at a liquid/air interface by a simple injection assembly (IA) technique. The monolayer QD film was assembled and passivated by a simple n-butylamine injection into ethylene glycol (EG), prompting the IA-QLEDs to exhibit excellent electrical performance. The as-fabricated IA-QLEDs outperform conventional SC-QLEDs with EQEs exceeding 24 % and significantly extended lifetimes. Furthermore, our method demonstrated its scalability (a defect-free 7×5 cm2 monolayer is fabricated), enabling the fabrication of large-area QD films with uniform morphology through a straightforward expansion of the film-forming container. This work proposes a general strategy for interfacial film formation and defect repair of QD film and holds significant promise for the practical application of high-performance QLEDs.