Independent Composition and Size Control for Highly Luminescent Indium-Rich Silver Indium Selenide Nanocrystals

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• 作者：Olesya Yarema ; Maksym Yarema ; Deniz Bozyigit ; Weyde M. M. Lin ; Vanessa Wood
• 刊名：ACS Nano
• 出版年：2015
• 出版时间：November 24, 2015
• 年：2015
• 卷：9
• 期：11
• 页码：11134-11142
• 全文大小：703K
• ISSN：1936-086X

文摘

Ternary I鈥揑II鈥揤I nanocrystals, such as silver indium selenide (AISe), are candidates to replace cadmium- and lead-based chalcogenide nanocrystals as efficient emitters in the visible and near IR, but, due to challenges in controlling the reactivities of the group I and III cations during synthesis, full compositional and size-dependent behavior of I鈥揑II鈥揤I nanocrystals is not yet explored. We report an amide-promoted synthesis of AISe nanocrystals that enables independent control over nanocrystal size and composition. By systematically varying reaction time, amide concentration, and Ag- and In-precursor concentrations, we develop a predictive model for the synthesis and show that AISe sizes can be tuned from 2.4 to 6.8 nm across a broad range of indium-rich compositions from AgIn₁₁Se₁₇ to AgInSe₂. We perform structural and optical characterization for representative AISe compositions (Ag_0.85In_1.05Se₂, Ag₃In₅Se₉, AgIn₃Se₅, and AgIn₁₁Se₁₇) and relate the peaks in quantum yield to stoichiometries exhibiting defect ordering in the bulk. We optimize luminescence properties to achieve a record quantum yield of 73%. Finally, time-resolved photoluminescence measurements enable us to better understand the physics of donor鈥揳cceptor emission and the role of structure and composition in luminescence.