Filling Chlorine Vacancy with Bromine: A Two-Step Hot-Injection Approach Achieving Defect-Free Hybrid Halogen Perovskite Nanocrystals

Autor: Xiaochen Wang, Tianxin Bai, Xuan Meng, Sujun Ji, Ruiling Zhang, Daoyuan Zheng, Bin Yang, Junke Jiang, Ke-li Han, Feng Liu
Přispěvatelé: Shandong University, Dalian Institute of Chemical Physics (DICP), Chinese Academy of Sciences [Changchun Branch] (CAS), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Eindhoven University of Technology [Eindhoven] (TU/e), National Natural Science Foundation of China [22179072, 22088102], Natural Science Foundation of Shandong Province [ZR2021QF006], Outstanding Youth Science Foundation of Shandong Province (Overseas) [2022HWYQ-006], Qilu Youth Scholar Foundation of Shandong University [62460082163114]
Rok vydání: 2022
Předmět:
Zdroj: ACS Applied Materials & Interfaces
ACS Applied Materials & Interfaces, 2022, 14 (41), pp.46857-46865. ⟨10.1021/acsami.2c12375⟩
ISSN: 1944-8252
1944-8244
DOI: 10.1021/acsami.2c12375
Popis: International audience; Mixed-halide (Cl and Br) perovskite nanocrystals (NCs) are of particular interest because they hold great potential for use in high-efficiency blue light-emitting diodes (LEDs). Generally, mixed-halide compounds are obtained by either a one-step synthesis with simultaneous addition of both halide precursors or a postsynthetic anion exchange using the opposite halogen. However, both strategies fail to prevent the formation of deep-level Cl vacancy defects, rendering the photoluminescence quantum yields (PLQYs) typically lower than 30%. Here, by optimizing both thermodynamic and kinetic processes, we devise a two-step hot-injection approach, which simultaneously realizes Cl vacancy filling and efficient anion exchange between Cl- and Br-. Both the identity of Br precursors and their injection temperature are revealed to be critical in transforming those highly defective CsPbCl3 NCs to defect-free CsPb(Cl/Br)(3). The optimally synthesized NCs exhibit a saturated blue emission at similar to 460 nm with a near-unity PLQY and a narrow emission bandwidth of 18 nm, which represents one of the most efficient blue emitters reported so far. The turn-on voltage of the ensuing LEDs is similar to 4.0 V, which is lower than those of most other mixed-halide perovskites. In addition, LEDs exhibit a stable electroluminescence peak at 460 nm under a high bias voltage of 8.0 V. We anticipate that our findings will provide new insights into the materials design strategies for producing high-optoelectronic-quality Cl-containing perovskites.
Databáze: OpenAIRE
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