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Tailoring the Energy Landscape in Quasi-2D Halide Perovskites Enables Efficient Green-Light Emission
- Tailoring the Energy Landscape in Quasi-2D Halide Perovskites Enables Efficient Green-Light Emission
- Quan L.N.; Zhao Y.; García De Arquer F.P.; Sabatini R.; Walters G.; Voznyy O.; Comin R.; Li Y.; Fan J.Z.; Tan H.; Pan J.; Yuan M.; Bakr O.M.; Lu Z.; Kim D.H.; Sargent E.H.
- Ewha Authors
- SCOPUS Author ID
- Issue Date
- Journal Title
- Nano Letters
- vol. 17, no. 6, pp. 3701 - 3709
- energy transfer; Light-emitting diodes; Monte Carlo; Perovskites; photoluminescence quantum yield; Quasi-2D perovskites
- American Chemical Society
- SCI; SCIE; SCOPUS
- Organo-metal halide perovskites are a promising platform for optoelectronic applications in view of their excellent charge-transport and bandgap tunability. However, their low photoluminescence quantum efficiencies, especially in low-excitation regimes, limit their efficiency for light emission. Consequently, perovskite light-emitting devices are operated under high injection, a regime under which the materials have so far been unstable. Here we show that, by concentrating photoexcited states into a small subpopulation of radiative domains, one can achieve a high quantum yield, even at low excitation intensities. We tailor the composition of quasi-2D perovskites to direct the energy transfer into the lowest-bandgap minority phase and to do so faster than it is lost to nonradiative centers. The new material exhibits 60% photoluminescence quantum yield at excitation intensities as low as 1.8 mW/cm2, yielding a ratio of quantum yield to excitation intensity of 0.3 cm2/mW; this represents a decrease of 2 orders of magnitude in the excitation power required to reach high efficiency compared with the best prior reports. Using this strategy, we report light-emitting diodes with external quantum efficiencies of 7.4% and a high luminescence of 8400 cd/m2. © 2017 American Chemical Society.
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