AbstractMolecular additives are widely utilized to minimize non-radiative recombination in metal halide perovskite emitters due to their passivation effects from chemical bonds with ionic defects. However, a general and puzzling observation that can hardly be rationalized by passivation alone is that most of the molecular additives enabling high-efficiency perovskite light-emitting diodes (PeLEDs) are chelating (multidentate) molecules, while their respective monodentate counterparts receive limited attention. Here, we reveal the largely ignored yet critical role of the chelate effect on governing crystallization dynamics of perovskite emitters and mitigating trap-mediated non-radiative losses. Specifically, we discover that the chelate effect enhances lead-additive coordination affinity, enabling the formation of thermodynamically stable intermediate phases and inhibiting halide coordination-driven perovskite nucleation. The retarded perovskite nucleation and crystal growth are key to high crystal quality and thus efficient electroluminescence. Our work elucidates the full effects of molecular additives on PeLEDs by uncovering the chelate effect as an important feature within perovskite crystallization. As such, we open new prospects for the rationalized screening of highly effective molecular additives.
|Original language||English (US)|
|State||Published - Aug 10 2021|
Bibliographical noteKAUST Repository Item: Exported on 2021-08-12
Acknowledgements: The authors thank Prof. Annamaria Petrozza, Dr. Tiankai Zhang for valuable discussions, and Kaichuan Wen and Prof. Jianpu Wang for help with the PLQE measurements. We acknowledge the support from the ERC Starting Grant (No. 717026), the Swedish Energy Agency Energimyndigheten (Nos. 48758-1 and 44651-1), Swedish Research Council VR, NanoLund, and the Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linköping University (Faculty Grant SFO-Mat-LiU No. 2009-00971). The authors would like to thank the NCD-SWEET beamline at ALBA Synchrotron from Spain for providing the beamtime. J.Y, O.F.M., and O.M.B. acknowledge the Supercomputing Laboratory at KAUST for their computational and storage resources. Y.Z., L.C., and B.S. thanks the National Natural Science Foundation of China (91833303, 61974098, 62005126), the National Key Research and Development Program (2016YFA0201900), Jiangsu High Educational Natural Science Foundation (18KJA430012), the 111 Program and Collaborative Innovation Center of Suzhou Nano Science and Technology, and Collaborative Innovation Center of Suzhou Nano Science & Technology. J.A.S. acknowledges financial support from the Research Foundation - Flanders (FWO: grant No.’s 12Y7218N and 12Y7221N). M.B.J.R. acknowledges financial support from the Research Foundation - Flanders (FWO, G098319N) and the KU Leuven Research Fund (C14/19/079). Y.Z. (No. 201806920071), P.T. (No. 201906830040, J.L. (No. 201608530162), W.L. (No. 201806460021) also thank the financial support from China Scholarship Council. F.G. is a Wallenberg Academy Fellow
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)