In this work 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4 ], an ionic liquid)/Triton X-100 (TX-100)/cyclohexane microemulsions have been prepared and characterized by phase behavior, conductivity measurement, dynamic light scattering, freeze-fracturing electron microscopy, and UV-vis techniques, and our attention is concentrated on the microemulsions with the ionic liquid as the nano-sized polar domains.

Halogen vacancies are of great concern in blue‐emitting perovskite quantum‐dot light‐emitting diodes because they affect their efficiency and spectral shift. Here, an enriched‐bromine surface state is realized using a facile strategy that employs a PbBr2 stock solution for anion exchange based on Cd‐doped perovskite quantum dots. It is found that the doped Cd ions are expected to reduce the formation energy of halogen vacancies filled by the external bromine ions, and the excess free bromine ions in solution are enriched in the surface by anchoring with halogen vacancies as sites, accompanied with the shedding of surface long‐chain ligands during the anion exchange process, resulting in a Br‐rich and “neat” surface. Moreover, the surface state exhibits good passivation of the surface defects of the controlled perovskite QDs and simultaneously increases the exciton binding energy, leading to excellent optical properties and stability. Finally, the sky‐blue emitting perovskite quantum‐dot light‐emitting diodes (QLEDs) (490 nm) are conducted with a record external quantum efficiency of 14.6% and current efficiency of 19.9 cd A−1. Meanwhile, the electroluminescence spectra exhibit great stability with negligible shifts under a constant operating voltage from 3 to 7 V. This strategy paves the way for improving the efficiency and stability of perovskite QLEDs.

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The effect of compressed CO2 and ethylene on the properties of Triton X-100/cyclohexane/water systems was studied at different temperatures and pressures. Surprisingly, it was discovered that the compressed gases had the functions of co-surfactants. At suitable pressures, the water-to-surfactant molar ratio (W0) was enhanced significantly by the dissolution of the gas in the solution. The microenvironment in the reverse micelles was investigated by UV-visible spectroscopy by using methyl orange (MO) as a probe. The influence of n-hexane, Na2CO3, NaHCO3, H2C2O4, and CaCl2 at various concentrations on the solubilization of water in the absence of compressed gases was also investigated in order to obtain some information about the mechanism of the interesting phenomenon. This new route to stabilize reverse micelles may have potential applications to other similar systems. Moreover, the results of this work provide some useful information to get insight into the mechanism of co-surfactants, because a conventional co-surfactant usually contains both polar group and hydrocarbon chain, and it is very difficult to clarify the functions these two groups, while the gases used in this work are small nonpolar molecules, which solely have the function of the hydrocarbon chain in a co-surfactant.

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