Inkjet-Printed Full-Color Matrix Quasi-Two-Dimensional Perovskite Light-Emitting Diodes.

Full-color matrix devices based on perovskite light-emitting diodes (PeLEDs) formed via inkjet printing are increasingly attractive due to their tunable emission, high color purity, and low cost. A key challenge for realizing PeLED matrix devices is achieving high-quality perovskite films with a favorable emission structure via inkjet printing techniques. In this work, a narrow phase distribution, high-quality quasi-two-dimensional (quasi-2D) perovskite film without a "coffee ring" was obtained via the introduction of a phenylbutylammonium cation into the perovskite and the use of a vacuum-assisted quick-drying process.

Effects of UV Irradiation and Storage on the Performance of Inverted Red Quantum-Dot Light-Emitting Diodes.

We report the effects of ultraviolet (UV) irradiation and storage on the performance of ZnO-based inverted quantum-dot light-emitting diodes (QLEDs). The effects of UV irradiation on the electrical properties of ZnO nanoparticles (NPs) were investigated. We demonstrate that the charge balance was enhanced by improving the electron injection.

Effects of ZnMgO Electron Transport Layer on the Performance of InP-Based Inverted Quantum Dot Light-Emitting Diodes.

An environment-friendly inverted indium phosphide red quantum dot light-emitting diode (InP QLED) was fabricated using Mg-doped zinc oxide (ZnMgO) as the electron transport layer (ETL). The effects of ZnMgO ETL on the performance of InP QLED were investigated. X-ray diffraction (XRD) analysis indicated that ZnMgO film has an amorphous structure, which is similar to zinc oxide (ZnO) film.

Bifacial passivation towards efficient FAPbBr-based inverted perovskite light-emitting diodes.

A unique technique to passivate both bottom and top sides of perovskite has been successfully developed to achieve highly efficient inverted perovskite light-emitting diodes (PeLEDs). For the bottom passivation, an organic/inorganic hybrid electron transporting layer (ETL) replaces the widely adopted inorganic ETL to overcome the disadvantages of the pure inorganic ETL. The ZPM (ZnO-in-polymer matrix) ETL, which consists of ZnO nanoparticles blended into polyvinylpyrrolidone, not only passivates the surface defects of ZnO nanoparticles, but also improves the morphology and stability of FAPbBr film.

All-Solution-Processed Pure Formamidinium-Based Perovskite Light-Emitting Diodes.

All-solution-processed pure formamidinium-based perovskite light-emitting diodes (PeLEDs) with record performance are successfully realized. It is found that the FAPbBr device is hole dominant. To achieve charge carrier balance, on the anode side, PEDOT:PSS 8000 is employed as the hole injection layer, replacing PEDOT:PSS 4083 to suppress the hole current.

Highly Efficient All-Solution Processed Inverted Quantum Dots Based Light Emitting Diodes.

In all-solution processed inverted quantum dots based light emitting diodes (QLEDs), the solvent erosion on the quantum dot (QD) layer prevents devices from reaching high performance. By employing an orthogonal solvent 1,4-dioxane for the hole transport layer (HTL) poly(9-vinlycarbazole) (PVK), the external quantum efficiencies (EQE) of red QLED is increased 4-fold, while the luminous efficiencies (LE) of blue QLED is enhanced by 25 times, compared to the previous devices' record. To further improve the device efficiency and reduce the efficiency roll-off, solution processed PVK/poly [(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(p-butylphenyl))diphenylamine)] (TFB) double-layer HTL is introduced to facilitate hole injection with stepwise energy level.