Surface‐Passivated Cesium Lead Halide Perovskite Quantum Dots: Toward Efficient Light‐Emitting Diodes with an Inverted Sandwich Structure. Issue 14 (6th May 2018)

• Record Type: Journal Article
• Authors: Chen, Weiwei; Tang, Xiaosheng; Wangyang, Peihua; Yao, Zhiqiang; Zhou, Dan; Chen, Fenggui; Li, Shiqi; Lin, Hao; Zeng, Fanju; Wu, Daofu; Sun, Kuan; Li, Meng; Huang, Yi; Hu, Wei; Zang, Zhigang; Du, Juan
• Is Part Of: Advanced optical materials. Volume 6:Issue 14(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-05-06
• Subjects: CsPbBr3 -- di‐dodecyl dimethyl ammonium bromide -- ligand exchange -- light‐emitting diodes -- quantum dots; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.201800007
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract: In recent years, metal‐halide perovskite quantum dots (QDs) have been broadly applied in optoelectronic fields due to their fascinating characteristics, such as high photoluminescence quantum yields, tunable bandgaps, and low‐cost solution processing. Here, a facile ligand‐exchange strategy is employed for the fabrication of CsPbBr3 QDs capped with di‐dodecyl dimethyl ammonium bromide. It is demonstrated that the treated QDs' film becomes more compact with higher electron mobility and shorter lifetime. Besides, a reduced conduction band minimum value (0.28 eV) of perovskite QDs' film provides an efficient electron injection to them from ZnO nanoparticles. Through using the well‐passivated QDs' film, electroluminescence QD light‐emitting diode (QLED) devices with an indium tin oxide/ZnO/CsPbBr3 QDs/MoO3 /4, 4′‐bis(carbazole‐9‐yl)biphenyl/Al inverted sandwich structure are achieved. The as‐prepared QLED device exhibits a maximum current efficiency of 0.62 cd A −1 and an external quantum efficiency of 0.58%, which is nearly nine times higher than that of the device based on unmodified QDs. More importantly, the stability testing results demonstrate that the QLED can be operated for more than 20 min under ambient conditions without any encapsulation. This provides an alternative route for highly efficient perovskite‐based LED with inverted sandwich structures. Abstract : A facile ligand exchange method is adopted to fabricate di‐dodecyl dimethyl ammonium bromide treated CsPbBr3 quantum dots (QDs). The treated QDs films exhibit a low root‐mean‐square roughness of only 3.1 nm. Using the treated QDs, a bright light‐emitting diode with an inverted structure shows a maximum luminous efficiency of 0.62 cd A ‐1 and an external quantum efficiency of 0.58%.