Stable, Efficient, and All-Solution-Processed Quantum Dot Light-Emitting Diodes with Double-Sided Metal Oxide Nanoparticle Charge Transport Layers

Abstract

An efficient and stable quantum dot lightemitting diode (QLED) with double-sided metal oxide (MO) nanoparticle (NP) charge transport layers is fabricated by utilizing the solution-processed tungsten oxide (WO 3 ) and zinc oxide (ZnO) NPs as the hole and electron transport layers, respectively. Except for the electrodes, all other layers are deposited by a simple spin-coating method. The resulting MO NP-based QLEDs show excellent device performance, with a peak luminance of 21300 cd/m 2 at the emission wavelength of 516 nm, a maximal current efficiency of 4.4 cd/ A, and a low turn-on voltage of 3 V. More importantly, with the efficient design of the device architecture, these devices exhibit a significant improvement in device stability and the operational lifetime of 95 h measured at room temperature can be almost 20-fold longer than that of the standard device.

Engineering of Semiconductor Nanocrystals for Light Emitting Applications

“…Other deposition processes involve full solution processing architectures, using the spin casting technique for the deposition of single colour QDs in each subpixel [137,139], or the deposition of multiple stacked layers by combining solution/vacuum methods [140]. Recently, Lee at al.…”

Solution-Processable MoO<italic>x</italic>for Efficient Light-Emitting Diodes Based on Giant Quantum Dots

“…However, their EL performance is generally far from that of the conducting polymer-based device. Furthermore, the reported work function (WF) of WO3 NPs was 5.15 eV, lower than the highest occupied molecular orbital (HOMO) level of the polymeric hole transport poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)-benzidine] (poly-TPD) [12]. Molybdenum oxide, possessing high work function and well-developed solution-processable precursors, is investigated as one of the promising candidates for electronic applications.…”

“…Though these materials are efficient p-type semiconductors, the process is generally not a cost-effective fabrication. Following these ideas, recently solution-processable WO3 NPs, and NiO via sol-gel processes [12][13][14] have also been applied and highly appreciated as potential stable hole injection materials for QLEDs. However, their EL performance is generally far from that of the conducting polymer-based device.…”

Quantum Dot Light-Emitting Diode with Ligand-Exchanged ZnCuInS₂ Quantum Dot

“…Semi- conductor QDs have several advantages compared with organic molecules, such as long-term stability [2], the possibility of solution processing, and controlled photoluminescence (PL) spectra by changing the core diameter [3]. By now, all-solution-processed devices [4], near-infrared emitters [5], and flexible device structures [6] have all been demonstrated with QLEDs.…”