Ionic Liquid Passivation Eliminates Low‑<i>n</i> Quantum Well Domains in Blue Quasi-2D Perovskite Films

In quasi-two-dimensional (quasi-2D) perovskite films, carriers transport in the cascade structural systems involving various quantum wells (QWs) n, but their efficiency is limited by the severe nonradiative recombination within plentiful n = 1, 2, 3 domains induced by traditional ammonium bromide passivation. Here, we fabricate the quasi-2D films with the elimination of n = 1, 2, 3 domains by introducing the ionic liquid n-butylamine acetate (BAAc) instead of n-butylamine hydrobromide (BABr), which increases the photoluminescence quantum yield (PLQY) and lowers the surface roughness of films. Due to the anion exchange between BAAc and methylamine hydrobromide (MABr), BAAc exhibits a sole passivation effect on methylamine-based perovskites. As a result, the ionic liquid-derived perovskite light-emitting diodes (PeLEDs) display blue emission at 479 nm and show significantly improved performance on external quantum efficiency (EQE) and luminance. Our finding provides insights into the passivating effect of ionic liquid on quasi-2D perovskites and will benefit fabricating PeLEDs with enhanced performance

The influence of working air gap on the deviation between the tested electromagnetic force of electromagnet with variable pole area and the tested electromagnetic force of planar pole electromagnet.

The influence of working air gap on the deviation between the tested electromagnetic force of electromagnet with variable pole area and the tested electromagnetic force of planar pole electromagnet.</p

Cross-sectional scheme of electromagnetic diaphragm pump with electromagnet with variable pole area.

1- pump body; 2-single-direction valve; 3-diaphragm; 4-spring; 5-electromagnetic coil; 6-ejector pin; 7-the iron core; 8-magnetic isolation ring; 9-the inner armature; 10-the outer armature; 11-sleeve.</p

Comparison of the electromagnetic force between the calculations results with the experimental results at different working air gap between the outer armature and the iron core.

Comparison of the electromagnetic force between the calculations results with the experimental results at different working air gap between the outer armature and the iron core.</p

The effect of working air gap on the deviation between the tested electromagnetic force of electromagnet with variable pole area and the tested electromagnetic force of planar pole electromagnet.

The effect of working air gap on the deviation between the tested electromagnetic force of electromagnet with variable pole area and the tested electromagnetic force of planar pole electromagnet.</p

The effect of working air gap on the tested electromagnetic forces of electromagnet with variable pole area and planar pole electromagnet.

The effect of working air gap on the tested electromagnetic forces of electromagnet with variable pole area and planar pole electromagnet.</p

The parameters of electromagnet prototype with variable pole area.

The parameters of electromagnet prototype with variable pole area.</p

The effect of working air gap on the tested electromagnetic forces of electromagnet with variable pole area and planar pole electromagnet.

The effect of working air gap on the tested electromagnetic forces of electromagnet with variable pole area and planar pole electromagnet.</p

The parameters of the displacement sensor and the tension sensor.

The parameters of the displacement sensor and the tension sensor.</p

The main parameters of electromagnet with variable pole area.

The main parameters of electromagnet with variable pole area.</p