Ion-pair pinning on perovskite quantum dots for high-efficiency air-processed light-emitting diodes with Rec. 2020 compliance

TL;DR

A new method enables the production of efficient light-emitting diodes using perovskite quantum dots in normal air, reducing costs and improving scalability.

Contribution

An ion-pair pinning strategy is introduced to stabilize perovskite quantum dots during air processing.

Findings

The method achieves high external quantum efficiency of 21.3% in air-processed QLEDs.

The QLEDs meet Rec. 2020 color standards with a peak luminance of over 3 × 10⁴ cd m⁻².

The strategy eliminates the need for inert gas during fabrication.

Abstract

Perovskite quantum dot light-emitting diodes (QLEDs) offer superior efficiency and high colour purity, making them promising candidates for next-generation lighting and display technologies. However, fabricating the emissive perovskite quantum dot (QD) layer typically requires a protective atmosphere due to its air sensitivity, thereby increasing production costs and limiting industrial scalability. Here, we propose an ion-pair pinning strategy by using tetraalkylammonium triflate (NR4OTf) to enable ambient-air processing of formamidinium lead bromide (FAPbBr3) QD films. The trifluoromethanesulfonic acid anions (OTf−) hydrogen bond with FA+, inhibiting its detachment and passivating the uncoordinated Pb2+, while the tetraalkylammonium cations (NR4+) serve as X-type ligands to inhibit deprotonation. This dual ion-pair pinning effect stabilises the QD lattice and provides surface resistance to moisture and oxygen, thereby improving the uniformity, stability, and optoelectronic performance of air-processed QD films. The as-constructed air-processed QLED achieves a high external quantum efficiency (EQE) of 21.3% and a peak luminance of over 3 × 104 cd m−2 at 529 nm with Rec. 2020 compliance (EQE of 23.9% and luminance of over 8 × 104 cd m−2 for the N2-processed QLED). Our work eliminates the reliance on inert gas protection in perovskite QLED fabrication, laying a foundation for their low-cost, large-scale manufacturing and expansion into diversified applications.

An ion-pair pinning strategy is proposed for air-processed FAPbBr3 quantum dot light-emitting diodes with Rec. 2020 compliance, eliminating inert gas dependence for low-cost scalable manufacturing.

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