Quasi-two-dimensional (quasi-2D) perovskites are attracting much attention due to their impressive luminescence properties. However, the introduction of insulating bulky cations reduces the charge transport property of mixeddimensional perovskites and leads to lowered brightness and increased turn-on voltage. The trade-off between high photoluminescence quantum yield (PLQY) and electrical conductivity should be well manipulated to obtain high-performance perovskite light-emitting diodes (PeLEDs). Herein, quasi-2D perovskite BA 2 (CsPbBr 3 ) n-1 PbBr 4 -PEO with high PLQY and excellent carrier injection efficiency is demonstrated by incorporating bulky n-butylammonium bromide (BABr), CsPbBr 3 , and polyethylene oxide (PEO). BA can intercalate into the three-dimensional perovskite framework to form a layered (quasi-2D) perovskite structure. The ion conductive polymer PEO is used to protect quasi-2D perovskite crystals. Additional BABr is removed by using anhydrous isopropyl alcohol as a washing agent due to its selective dissolubility. By carefully modulating the optical and electrical properties of quasi-2D perovskite films, the maximum luminance of PeLEDs is dramatically enhanced from 191 to 33533 cd m −2 , which is the brightest green quasi-2D PeLED reported thus far, leading to an increase in external quantum efficiency from 1.81% to 8.42%. This work provides a promising route to control the optical and electrical properties of quasi-2D perovskite films for high-performance optoelectronic devices.

For quasi‐2D perovskite light‐emitting diodes, the introduction of insulating bulky cation reduces the charge transport property, leading to lowered brightness and increased turn‐on voltage. Herein, a dual‐ligand strategy is adopted to prepare perovskite films by using an appropriate ratio of i‐butylammonium (iBA) and phenylethylammonium (PEA) as capping ligands. The introduction of iBA enhances the binding energy of the ligands on the surface of the quasi‐2D perovskite, and effectively controls the proportion of 2D perovskite to allow more efficient energy transfer, resulting in the great enhancement of the electric and luminescent properties of the perovskite. The photoluminescence (PL) mapping of the perovskite films exhibits that enhanced photoluminescence performance with better uniformity and stronger intensity can be achieved with this dual‐ligand strategy. By adjusting the proportion of the two ligands, sky‐blue perovskite light‐emitting diodes (PeLEDs) with electroluminescence (EL) peak located 485 nm are achieved with a maximum luminance up to 1130 cd m−2 and a maximum external quantum efficiency (EQE) up to 7.84%. In addition, the color stability and device stability are significantly enhanced by using a dual‐ligand strategy. This simple and feasible method paves the way for improving the performance of quasi‐2D PeLEDs.

A simple method based on a hydrothermal process using alkali salts as mineralizers is proposed for the synthesis of aligned bunches of boehmite (gamma-AlOOH) nanowires without a template's assistance. Most bunches of aligned boehmite nanowires are constructed by two separated shorter bundles with widths of 700 to approximately 800 nm and lengths of about 1 microm. XRD patterns, FTIR spectra, and SEM and TEM images were used to characterize the products. The specific surface area and pore-size distribution of the obtained product as determined by gas-sorption measurements show that the boehmite bundles possess a high BET surface area and porosity properties. The importance of adding Na2B4O7 salts for the formation of bundle morphologies has been discussed.

For blue quantum dot (QD) light-emitting diodes (QLEDs), the imbalance of charges transport and injection severely affects their efficiency and lifetime. A better charge balance can be realized by improving hole injection while suppressing redundant electrons. Introducing dopants into charge transport layers (CTLs) is an effective and simple strategy to modulate the charge injection barrier and mobility. In this work, optoelectronic simulation is performed to investigate the change in physical process within the devices upon CTL doping. The results confirm that the charge distribution in the QD layer is more balanced and the recombination rate is greatly improved. Under the guidance of theoretical simulation, high-performance blue QLEDs were achieved by fine-tuning the charge balance through CTL doping. The luminance and external quantum efficiency have been dramatically increased from 18 679 to 34 874 cd/m2 and from 4.7 to 10.7%, respectively. The operation lifetime is also improved ∼3.5 times due to the more balanced charge injection.