Rapid Automated Materials Synthesis Instrument: Exploring the Composition and Heat-Treatment of Nanoprecursors Toward Low Temperature Red Phosphors

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• 作者：Tian Lin ; Suela Kellici ; Kenan Gong ; Kathryn Thompson ; Julian R. G. Evans ; Xue Wang ; Jawwad A. Darr
• 刊名：Journal of Combinatorial Chemistry
• 出版年：2010
• 出版时间：May 10, 2010
• 年：2010
• 卷：12
• 期：3
• 页码：383-392
• 全文大小：455K
• 年卷期：v.12,no.3(May 10, 2010)
• ISSN：1520-4774

文摘

We report on the commissioning experimental run of the rapid automated materials synthesis instrument (RAMSI), a combinatorial robot designed to manufacture, clean, and print libraries of nanocrystal precursor solid compositions. The first stage of RAMSI, parallel synthesis, uses a fully automated high throughput continuous hydrothermal (HiTCH) flow reactor for automatic metal salt precursor mixing, hydrothermal flow reaction, and sample slurry collection. The second stage of RAMSI provides integrated automated cleanup, and the third section is a ceramic printing function. Nanocrystal precursor solid ceramics were synthesized from precursor solutions and collected into 50 mL centrifuge tubes where they were cleaned by multiple centrifugation and redispersion cycles (monitored by intelligent scanning turbidimetry) and printed with an automated pipette. Eight unique compositions of a model phosphor library comprising pure nano-Y(OH)₃ and Eu³⁺ doped-yttrium hydroxide, Y(OH)₃:Eu³⁺ nanocrystal precursor solid were synthesized (with 2 centrifuge tubes’ worth collected per composition), processed, and printed in duplicate as 75, 100, and 125 μL dots in a 21.6 ks (6 h) experiment (note: the actual time for synthesis of each sample tube was only 12 min so up to 60 compositions could easily be synthesized in 12 h if one centrifuge tube per composition was collected instead). The Y(OH)₃:Eu³⁺ samples were manually placed in a furnace and heat-treated in air for 14.4 ks (4 h) in the temperature range 200−1200 at 100 °C intervals (giving a total of 84 samples plus one as-prepared pure Y(OH)₃ sample). The as-prepared and heat-treated ceramic samples were affixed to 4 mm wide hemispherical wells in a custom-made aluminum well-plate and analyzed using a fluorescence spectrometer. When the library was illuminated with a 254 nm light source (and digitally imaged and analyzed), the 3 mol % Eu³⁺ sample heat-treated at 1200 °C gave the most intense fluorescence (major red peak at 612 nm); however, an identical nanocrystal precursor heat-treated at only 500 °C (identified as Y₂O₃:Eu³⁺ after heat treatment) was the brightest phosphor under illumination of the samples heat-treated at or below 1000 °C.