Researchers at Soochow University’s Institute of Functional Nano & Soft Materials have reported a solution to a persistent challenge in near-infrared electroluminescence: efficiency roll-off, a decline in performance that has limited the practical application of this technology. The team details in Light Science & Applications, published May 7th, 2026, how an “ionic liquid-mediated surface reconstruction strategy” effectively stabilizes perovskite quantum dots while simultaneously enhancing charge transport. This approach utilizes 1-methyl-3-propylimidazolium iodide (MPII) to suppress defect formation and create a protective layer, resulting in a twofold reduction in trap density and a tenfold increase in conductivity. This advancement enables more efficient near-infrared LEDs suitable for both bioimaging and information encryption.
Ionic Liquid Mediated Surface Reconstruction of Perovskite Quantum Dots
Published in Light Science & Applications on May 7th, 2026, in Volume 15, Issue 1, article 221, the team reports a peak external quantum efficiency of 24.8% for their near-infrared LEDs, a significant leap forward in the field. This advancement addresses a critical limitation of perovskite quantum dot technology: efficiency roll-off, where performance degrades at higher brightness levels. The researchers tackled this issue with what they describe as an “ionic liquid-mediated surface reconstruction strategy,” utilizing 1-methyl-3-propylimidazolium iodide (MPII) to simultaneously stabilize the quantum dot surface and improve charge transport. Incorporating MPII into the manufacturing process suppresses defect formation and creates a protective layer in situ, reducing surface traps and preserving the structural integrity of the quantum dots.
The implications of this work extend beyond performance gains; the team fabricated large-area devices, reaching 900 mm², with efficiencies up to 20%, demonstrating practical applications in both biomedical imaging and information encryption. Maintaining approximately 20% efficiency at a radiance of 10 W sr⁻¹ m⁻², the devices represent the lowest efficiency roll-off yet reported for perovskite quantum dot-based near-infrared LEDs, opening possibilities for more versatile and powerful optoelectronic applications.
The fabricated NIR LEDs achieve a record EQE of 24.8%, maintaining ~20% EQE at a radiance of 10 W sr – ¹ m – ²-representing the lowest efficiency roll-off for PQD-based NIR LEDs reported to date.
NIR Electroluminescence Achieves 24.8% EQE for Bioimaging & Encryption
The researchers achieved 24.8 percent efficiency with perovskite quantum dot LEDs. This efficiency level addresses a longstanding challenge in the field; previously, high performance was hampered by a decline in light output at higher brightness levels. The team, led by Tao Yang and Ya-Kun Wang, focused on stabilizing the perovskite quantum dots while simultaneously improving charge transport within the LED structure. Central to their success is an “ionic liquid-mediated surface reconstruction strategy” designed to mitigate defects that trap electrons and reduce light emission. This improvement isn’t merely a laboratory curiosity; the Jiangsu-based team demonstrated practical applications for the technology.
