Highly Luminescent WS2 Quantum Dots/ZnO Heterojunctions for Light Emitting Devices

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• 作者：Arup Ghorai ; Sayan Bayan ; Narendar Gogurla ; Anupam MidyaSamit K. Ray
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2017
• 出版时间：January 11, 2017
• 年：2017
• 卷：9
• 期：1
• 页码：558-565
• 全文大小：607K
• ISSN：1944-8252

文摘

Sonication induced vertical fragmentation of two-dimensional (2D) WS₂ nanosheets into highly luminescent, monodispered, zero-dimensional (0D) quantum dots (QDs) is reported. The formation of 0D structures from 2D sheets and their surface/microstructure characterization are revealed from their microscopic and spectroscopic investigations. Size dependent optical properties of WS₂ nanostructures have been explored by UV–vis absorption and photoluminescence spectroscopy. Interestingly, it is observed that, below a critical dimension (∼2 nm), comparable to the Bohr exciton radius, the tiny nanocrystals exhibit strong emission. Finally, the electroluminescence characteristics are demonstrated for the first time, by forming a heterojunction of stabilizer free WS₂ QDs and ZnO thin films. The signature of white light emission in the light emitting device is attributed to the adequate intermixing of emission characteristics of WS₂ QDs and ZnO. The observation of white electroluminescence may pave the way to fabricate prototype futuristic efficient light emitting devices.