Significant Lifetime Enhancement in QLEDs by Reducing Interfacial Charge Accumulation via Fluorine Incorporation in the ZnO Electron Transport Layer

ZnO nanoparticles are widely used for the electron transport layers(ETLs)of quantum dots light emitting devices(QLEDs).In this work we show that incorporating fluorine(F)into the ZnO ETL results in significant enhancement in device electroluminescence stability,leading to LT50 at 100 cd m^(−2) of 2,370,000 h in red QLED,47X longer than the control devices.X-ray photo-electron spectroscopy,time-of-flight secondary ion mass spectroscopy,photoluminescence and electrical measurements show that the F passivates oxygen vacancies and reduces electron traps in ZnO.Transient photoluminescence versus bias measurements and capacitance-voltage-luminance measurements reveal that the CF4 plasma-treated ETLs lead to increased electron concentration in the QD and the QD/hole transport layer interface,subsequently decreasing hole accumulation,and hence the higher stability.The findings provide new insights into the critical roles that optimizing charge distribution across the layers play in influencing stability and present a novel and simple approach for extending QLED lifetimes.

Overview of Future Antenna Design for Mobile Terminals

1.Introduction Over the years,antenna design for mobile terminals has become increasingly difficult.This is mainly attributed to the limited space available in such devices for the housing of multiple antennas with wide and multi-frequency band requirements.The coming fifth generation(5G)of wireless communications makes this issue even more challenging for mobile terminal antenna designers,since it requires a very large number of multiple input/multiple output(MIMO)antennas at sub-6 GHz frequency bands,as well as two or three antenna-in-package(AiP)modules at millimeter-wave frequency bands.In these antenna designs,the antennas must be small,compact,low profile,and lightweight,while maintaining wideband and multiband performance.Furthermore,for MIMO antenna design,although the antennas are placed very close together,a high degree of isolation between antennas must be satisfied,even within the same frequency bands.This article presents an overview of future antenna design for mobile terminals.

Highly efficient transparent quantum-dot light-emitting diodes based on inorganic double electron-transport layers

Herein,we report the fabrication of high-performance transparent quantum-dot light-emitting diodes(Tr-QLEDs)with ZnO/ZnMgO inorganic double electron-transport layers(ETLs).The ETLs effectively suppress the excess electron injection and facilitate charge balance in the Tr-QLEDs.The thick ETLs as buffer layers can also withstand the plasma-induced damage during the indium tin oxide sputtering.These factors collectively contribute to the development of Tr-QLEDs with improved performance.As a result,our Tr-QLEDs with double ETLs exhibited a high transmittance of 82%at 550 nm and a record external quantum efficiency of 11.8%,which is 1.27 times higher than that of the devices with pure ZnO ETL.These results indicate that the developed ZnO/ZnMgO inorganic double ETLs could offer promising solutions for realizing high-efficiency Tr-QLEDs for next-generation display devices.