Semiconductor colloidal quantum dots (CQDs) offer size- and composition-tunable luminescence of high colour purity. Importantly, their emission can be tuned deep into the second biological near-infrared (NIR-II) window (1,000–1,700 nm). However, applications are hindered by the low efficiencies achieved to date. Here, we report NIR-II CQD light-emitting diodes with an external quantum efficiency of 16.98% and a power conversion efficiency of 11.28% at wavelength 1,397 nm. This performance arises from device engineering that delivers a high photoluminescence quantum yield and charge balance close to unity. More specifically, we employed a binary emissive layer consisting of silica-encapsulated silver sulfide (Ag2S@SiO2) CQDs dispersed in a caesium-containing triple cation perovskite matrix that serves as an additional passivation medium and a carrier supplier to the emitting CQDs. The hole-injection contact also features a thin porphyrin interlayer to balance the device current and enhance carrier radiative recombination.
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The data that support the plots within this paper and other findings of this study are available from the corresponding authors upon reasonable request.
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A.G.M. and A.E.X.G. acknowledge financial support from Serrapilheira Institute (grant no. Serra-1709–17054). W.J.d.S. and F.K.S. acknowledge CAPES-PNPD project no. 3076/2010 for providing financial assistance. M.A.M.T. acknowledges Universiti Kebangsaan Malaysia project no. DIP-2018-009. H.P.K., B.S.K. and A.R.b.M.Y. acknowledge support from the Ministry of Trade, Industry and Energy (10052044) and Korea Display Research Corporation. This research has also been co‐financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH – CREATE – INNOVATE (project code T1EDK-01504). This work was also supported by the European Commission’s Seventh Framework Programme (FP7/2007–2013) under grant agreement no. 229927 (FP7-REGPOT-2008-1, Project BIO-SOLENUTI), also the Special Research Account of the University of Crete is gratefully acknowledged.
The authors declare no competing interests.
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Vasilopoulou, M., Kim, H.P., Kim, B.S. et al. Efficient colloidal quantum dot light-emitting diodes operating in the second near-infrared biological window. Nat. Photonics 14, 50–56 (2020). https://doi.org/10.1038/s41566-019-0526-z