Singlet and triplet harvesting enable efficient NIR-II quantum-dot electroluminescence

Journal article

Colloidal quantum dots (CQDs) are promising materials for constructing ‘second-window’ near-infrared (1000–1700 nm) light-emitting diodes (NIR-II LEDs), but their practical application has been hampered by low film external quantum efficiency (EQE). Here, we report a chemical strategy that incorporates photoactive fluorophores—spanning fluorescence, phosphorescence and thermally activated delayed fluorescence—into CQD films to boost NIR-II emission. Energy transfer from fluorophores (via both singlet and triplet pathways) raises the photoluminescence quantum efficiency of CQD to 85% beyond 1000 nm. As a result, these composite films power NIR-II LEDs with a record EQE of 25.3% for emission of >1000 nm, the highest among all LEDs with emission of >1000 nm. We further demonstrate the scalability of the approach by fabricating large-area (30 mm × 30 mm) NIR-II LEDs with uniform high performance.

Authors: Shen, W; Teale, S; Liu, Y; Pan, J; Yu, Y

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: National Science Review
• Volume: 13
• Issue: 3
• Pages: nwaf552
• Article number: nwaf552
• Publication date: 2025-12-04
• Acceptance date: 2025-12-02
• DOI: 10.1093/nsr/nwaf552
• EISSN: 2053-714X
• ISSN: 2095-5138
• Language: English
• Keywords: quantum dots; near-infrared; light-emitting diodes; electroluminescence; fluorophore