Improved Efficiency of All-Inorganic Quantum-Dot Light-Emitting Diodes via Interface Engineering

Abstract

As the charge transport layer of quantum dot (QD) light-emitting diodes (QLEDs), metal oxides are expected to be more stable compared with organic materials. However, the efficiency of metal oxide-based all-inorganic QLEDs is still far behind that of organic-inorganic hybrid ones. The main reason is the strong interaction between metal oxide and QDs leading to the emission quenching of QDs. Here, we demonstrated nickel oxide (NiO x )-based all-inorganic QLEDs with a maximum current efficiency of 20.4 cd A −1 and external quantum efficiency (EQE) of 5.5%, which is among the most efficient all-inorganic QLEDs. The high efficiency is mainly attributed to the aluminum oxide (Al 2 O 3 ) deposited at the NiO x /QDs interface to suppress the strong quenching effect of NiO x on the QD emission, together with the molybdenum oxide (MoO x ) that reduced the leakage current and facilitated hole injection, more than 300% enhancement was achieved compared with the pristine NiO x -based QLEDs. Our study confirmed the effect of decorating the NiO x /QDs interface on the performance enhancement of the all-inorganic QLEDs.

Mussel-Inspired Magnetic Dissolving Pulp Fibers Toward the Adsorption and Degradation of Organic Dyes

“…Adsorption is one of the most effective methods to treat organic dyes, and it is widely used because of its relatively low cost and easy operation. Various adsorbents have been designed to remove dyes in water and have considerable adsorption capacities, such as activated carbon ( Tang et al, 2017 ; Zhang et al, 2019 ; Soares et al, 2021 ), functional carbon materials ( Magno et al, 2020 ; Xing et al, 2020 ; Zhang et al, 2020 ), composite hydrogel ( Srivastava and Roy Choudhury, 2021 ), and metal oxide ( Rastogi et al, 2017 ; Xu et al, 2020 ; Şerban and Enesca, 2020 ). Among these methods, chemistry reduction has gained popularity because of its ease of use, high efficiency, clean processing, and low cost.…”

Ligand-assisted structure tailoring of highly luminescent Cu-In-Zn-S/ZnS//ZnS quantum dots for bright and stable light-emitting diodes

“…QD-based light-emitting diodes (QLEDs) as superior light sources have attracted huge interest, since the first device was reported ( Colvin et al, 1994 ; Deng et al, 2020 ). The high external quantum efficiency (EQE) and luminance have been achieved in red, green and blue QLEDs through the advances of device structure, QD material synthesis and surface ligand ( Qian et al, 2011 ; Li et al, 2018a ; Shen et al, 2019 ; Xu et al, 2020 ; Cheng et al, 2022 ; Lee et al, 2022 ; Meng et al, 2022 ). Yet almost all of the high performance QLEDs employed the Cd-based QDs as the emitting layer, which was limited by the “Restriction of Hazardous Substances” directive of the European Union.…”

Display illumination with modulated directional backlight

“…Alternatively, light sources can also function as pattern carriers, such as a light‐emitting diode (LED) display 3,4 . The illumination is usually referred to lamp lighting, LED lighting, 5–11 and recently to laser lighting 12 . The illuminating light now extends from incoherent to coherent light sources 13,14 .…”

“…Different illumination distribution of light may be required to meet variant display requirements in practice 15–18 . The illuminating technologies for displays are involving rapidly, but the improvement is mainly along the route for the performance in display features, such as dynamic range, color gamut, homogeneity, brightness, and efficiency 6–11,19,20 . Success has been achieved by controlling the illumination directionality using various techniques, such as headlamp, searchlight, the directional backlight (DB) illuminated displays, laser lighting, undersea lighting, and so on.…”