Abstract
Mixed halide (Br/Cl) perovskite nanocrystals (NCs) that represent an advanced blue emitter commonly suffer from spectral instability and poor lifespan; notably, the lack of understanding of the failure mechanisms of these devices has restricted the future progress. Here, we determine that the degradation of CsPbBrxCl3-x NCs containing blue light-emitting diodes (LEDs) is due to the combination of two effects. Cl- drift among adjoining NCs under an electric field is found to induce a Cl-deficient material region in multiple NC layers, which dominates the unstable electroluminescence and causes fast degradation in the corresponding devices. In comparison, the monolayer NC devices that feature restricted anion drift pathways exhibit better operational stability; however, excess hole injection is demonstrated to induce irreversible chlorine loss in NCs. Such a process that largely arises from electrochemical oxidation of Cl- initiates a mild device failure in operation of tens of minutes. Through revealing these mechanisms, we modulate the devices' construction and operational conditions to achieve a longer lifespan.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1348-1354 |
| Number of pages | 7 |
| Journal | ACS Energy Letters |
| Volume | 7 |
| Issue number | 4 |
| DOIs | |
| State | Published - Mar 17 2022 |
Bibliographical note
KAUST Repository Item: Exported on 2023-06-15Acknowledgements: S.Y., W.-S.S., Q.-S.T., J.-J.W., X.-D.W., C.Z., Z.-K.W., and L.-S.L. acknowledge financial support from the Natural Science Foundation of China (Nos. 51821002, 91733301, 61674109, 11675252, 11605278) and the National Key R&D Program of China (No. 2016YFA0202400). X.Z., J.L., and O.M.B. acknowledge the KAUST research translation funding. S.Y. and L.-S.C. acknowledge the 100 Talent Program of Chinese Academy of Sciences (Grant No. KY2060000185) and the National Natural Science Foundation of China (NSFC) (Grant No. 52103242). This work was supported by the Suzhou Key Laboratory of Functional Nano & Soft Materials, Collaborative Innovation Center of Suzhou Nano Science & Technology, the 111 Project. This work was done in part at the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36-08GO28308. J.M.L. acknowledges the Center for Hybrid Organic Inorganic Seminconductors for Energy (CHOISE), an Energy Frontier Research Center funded by the Office of Basic Energy Sciences, Office of Science, within the US DOE. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government.