Perovskite energy funnels for efficient light-emitting diodes

Mingjian Yuan, Li Na Quan, Riccardo Comin, Grant Walters, Randy Sabatini, Oleksandr Voznyy, Sjoerd Hoogland, Yongbiao Zhao, Eric M. Beauregard, Pongsakorn Kanjanaboos, Zhenghong Lu, Dong Ha Kim, Edward H. Sargent

Research output: Contribution to journalArticlepeer-review

1422 Scopus citations

Abstract

Organometal halide perovskites exhibit large bulk crystal domain sizes, rare traps, excellent mobilities and carriers that are free at room temperature - properties that support their excellent performance in charge-separating devices. In devices that rely on the forward injection of electrons and holes, such as light-emitting diodes (LEDs), excellent mobilities contribute to the efficient capture of non-equilibrium charge carriers by rare non-radiative centres. Moreover, the lack of bound excitons weakens the competition of desired radiative (over undesired non-radiative) recombination. Here we report a perovskite mixed material comprising a series of differently quantum-size-tuned grains that funnels photoexcitations to the lowest-bandgap light-emitter in the mixture. The materials function as charge carrier concentrators, ensuring that radiative recombination successfully outcompetes trapping and hence non-radiative recombination. We use the new material to build devices that exhibit an external quantum efficiency (EQE) of 8.8% and a radiance of 80W sr-1m-2. These represent the brightest and most efficient solution-processed near-infrared LEDs to date.

Original languageEnglish
Pages (from-to)872-877
Number of pages6
JournalNature Nanotechnology
Volume11
Issue number10
DOIs
StatePublished - 1 Oct 2016

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