47‐4: Aging Behaviors of QLED with Different Structures

Abstract

Quantum dot light-emitting diodes (QLEDs) are recognized as one of the candidates for the development of next generation displays. However the stability issue restricts their industrialization. In this work, we investigated the aging behaviors of QLEDs with different structures. We identified that the lifetime of QLEDs is greatly affected by the hole transport layer (HTL). In addition, we found that devices encapsulated with and without desiccant exhibit different aging behaviors. The use of desiccant improved the stability of the HTL, but the positive aging which could prolong the lifetime of devices was alleviated. On the other hand, device without desiccant exhibited positive aging behavior but the HTL was degraded rapidly. It is concluded that there is a trade-off between positive aging and stability of HTL.

Effect of Air Exposure of ZnMgO Nanoparticle Electron Transport Layer on Efficiency of Quantum-Dot Light-Emitting Diodes

“…One important factor limiting the performance of QLEDs with ZnMgO ETL is a hole leakage, which arises from trap-mediated transport. − It is known that H 2 O molecules passivate active sites in ZnMgO NPs, and therefore it is apparent that the difference between EQEs of devices produced in N 2 results from reduced hole leakage current . Our ZnMgO NPs are fabricated in the inert gas atmosphere (N 2 ) and are capped with acetic acid ligands as evidenced by symmetric (ν s ) and asymmetric (ν as ) stretching COO – bands in Fourier transform infrared (FTIR) spectra (Figure a).…”

“…Recently, a lot of attention has also been paid to encapsulation as a potential source of unwanted chemical moieties such as water or organic acids . For instance, it has been proposed that contamination with water, which is created by chemical reaction between the resin and ZnMgO electron transport layer (ETL), is a key factor influencing device lifetime. − Some authors have pointed to spontaneous interfacial reaction of ZnMgO with Al as a major cause of the aging process, while others proposed vacancy reduction in ZnMgO as a possible reason . Recently, a more sophisticated phenomenon such as resistive switching, i.e., electric-field-induced oxygen vacancies migration, which is an intrinsic property of ZnMgO, has been investigated as potentially detrimental to operational stability …”

Effect of using ink containing polyacrylate and silicone surfactant on the inkjet printing of quantum dot films

“…Quantum dots (QDs) are low-dimensional materials with excellent optical properties, including high color purity, stability, and tunable emission wavelength [1][2][3][4]. As an important class of photovoltaic materials [5], QDs can be fabricated into thin films.…”