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Interface Engineering of CsPbBr 3 Nanocrystal Light‐Emitting Diodes via Atomic Layer Deposition
Author(s) -
Zhou Binze,
Wang Zhaojie,
Geng Shicai,
Li Yun,
Wang Kai,
Cao Kun,
Wen Yanwei,
Chen Rong
Publication year - 2020
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.202000083
Subject(s) - electroluminescence , materials science , nanocrystal , atomic layer deposition , optoelectronics , perovskite (structure) , layer (electronics) , light emitting diode , quantum efficiency , diode , coating , charge carrier , quantum dot , nanotechnology , chemical engineering , engineering
Perovskite nanocrystal (PNC) suffers from solution corrosion and water/oxygen oxidation when used in light‐emitting diodes (LEDs). Atomic layer deposition (ALD) is applied to introduce Al 2 O 3 infilling and interface engineering for the CsPbBr 3 nanocrystal emission layers, and the inorganic electron transport layer‐based CsPbBr 3 –ZnMgO LED device is fabricated. The introduction of Al 2 O 3 ALD layers significantly improves the tolerance of CsPbBr 3 PNC thin films to polar solvents ethanol of ZnMgO during spin coating. The operation lifetime of ALD‐treated CsPbBr 3 PNC–ZnMgO LED is prolonged to about two orders of magnitude greater than that of the CsPbBr 3 PNC‐TPBi LED device with a largely improved external quantum efficiency (EQE) value. Moreover, the infilling of Al 2 O 3 into the CsPbBr 3 layer boosts the carrier mobility for more than 40 times inside the light‐emission layer. However, the interfacial carrier transport between different functional layers is hindered by the insulated Al 2 O 3 layer, which provides an effective barrier for excess electron transport. Such a favorable band alignment facilitates the carrier balance of the device and contributes to the improved electroluminescent performance of the device with ALD Al 2 O 3 interface engineering, which is further supported by theoretical device modeling. Herein, a facile method is provided to fabricate PNC‐LED devices with both high efficiency and long‐term lifetime.