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Bright CsPbI3 Perovskite Quantum Dot Light-Emitting Diodes with Top-Emitting Structure and a Low Efficiency Roll-Off Realized by Applying Zirconium Acetylacetonate Surface Modification

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journal contribution
posted on 30.03.2020, 15:10 by Min Lu, Jie Guo, Siqi Sun, Po Lu, Jinlei Wu, Yu Wang, Stephen V. Kershaw, William W. Yu, Andrey L. Rogach, Yu Zhang
Zirconium acetylacetonate used as a co-precursor in the synthesis of CsPbI3 quantum dots (QDs) increased their photoluminescence quantum efficiency to values over 90%. The top-emitting device structure on a Si substrate with high thermal conductivity (to better dissipate Joule heat generated at high current density) was designed to improve the light extraction efficiency making use of a strong microcavity resonance between the bottom and top electrodes. As a result of these improvements, light-emitting diodes (LEDs) utilizing Zr-modified CsPbI3 QDs with an electroluminescence at 686 nm showed external quantum efficiency (EQE) of 13.7% at a current density of 108 mA cm–2, which was combined with low efficiency roll-off (maintaining an EQE of 12.5% at a high current density of 500 mA cm–2) and a high luminance of 14 725 cd m–2, and the stability of the devices being repeatedly lit (cycled on and off at high drive current density) has been greatly enhanced.