Effect of Time-Dependent Characteristics of ZnO Nanoparticles Electron Transport Layer Improved by Intense-Pulsed Light Post-Treatment on Hole-Electron Injection Balance of Quantum-Dot Light-Emitting Diodes.

Young Joon Han,Byeong-Kwon Ju,Kyung-Tae Kang,Kwan Hyun Cho

doi:10.3390/ma13215041

Abstract

We investigated the effect of intense-pulsed light (IPL) post-treatment on the time-dependent characteristics of ZnO nanoparticles (NPs) used as an electron transport layer (ETL) of quantum-dot light-emitting diodes (QLEDs). The time-dependent characteristics of the charge injection balance in QLEDs was observed by fabrication and analysis of single carrier devices (SCDs), and it was confirmed that the time-dependent characteristics of the ZnO NPs affect the device characteristics of QLEDs. Stabilization of the ZnO NPs film properties for improvement of the charge injection balance in QLEDs was achieved by controlling the current density characteristics via filling of the oxygen vacancies by IPL post-treatment.

Highlights

Based on the excellent electroluminescence (EL) and material properties of quantum-dots (QDs), remarkable research results for quantum-dot light-emitting diodes (QLEDs) have been reported.In addition to sharp and pure color reproducibility due to the discontinuous bandgap structure, the material stability, based on the unique properties of inorganic materials, is driving the expectation that QDs will present a new paradigm for the display industry [1,2,3,4,5]
In the field of QLEDs, rather than deposition of a bulk ZnO layer, research is mainly focused on the formation of an electron transport layer (ETL) in nanoparticle form by a solution process [13,14]
Figure diagram in Figure shows that carrier transport and injection from the lower and upper layers of diagram in Figure 1 shows that carrier transport and injection from the lower and upper layers the of are complete, and that the can serve as an electron blocking layer the QD emission layer (EML) are complete, and that the hole transport layers (HTL) and ZnO NPs ETL can serve as an electron blocking (EBL)(EBL)

Summary

Introduction

Based on the excellent electroluminescence (EL) and material properties of quantum-dots (QDs), remarkable research results for quantum-dot light-emitting diodes (QLEDs) have been reported.In addition to sharp and pure color reproducibility due to the discontinuous bandgap structure, the material stability, based on the unique properties of inorganic materials, is driving the expectation that QDs will present a new paradigm for the display industry [1,2,3,4,5]. In the field of QLEDs, rather than deposition of a bulk ZnO layer, research is mainly focused on the formation of an ETL in nanoparticle form by a solution process [13,14]. In this case, despite having a relatively low electron mobility compared to that of bulk ZnO, it has the advantage of being able to use low annealing that does not damage the QDs. QLEDs require a stable charge injection balance with respect to time and environmental stability. To improve the Materials 2020, 13, 5041; doi:10.3390/ma13215041 www.mdpi.com/journal/materials

Methods

Results

Discussion

Conclusion