Strong and Tunable Blue Luminescence from Cd1-xZnxS Alloy Nanocrystallites Grown in Langmuir鈥揃lodgett Multilayers

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• 作者：Pavan K. Narayanam ; Purvesh Soni ; R. S. Srinivasa ; S. S. Talwar ; S. S. Major
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：February 28, 2013
• 年：2013
• 卷：117
• 期：8
• 页码：4314-4325
• 全文大小：786K
• 年卷期：v.117,no.8(February 28, 2013)
• ISSN：1932-7455

文摘

Cdb>1-xb>Znb>xb>S alloy nanocrystallites were grown in organic layered matrix by Hb>2b>S exposure of precursor CdA-ZnA Langmuir鈥揃lodgett multilayers at room temperature. The multilayers containing the alloy nanocrystallites were subsequently subjected to intercalation with Cd²⁺ ions followed by heat treatment up to 300 掳C. With variation of the Zn content of precursor multilayers, the alloy nanocrystallites exhibit changes in lattice constants as well as a shift of excitonic absorption and emission between the extreme values for CdS and ZnS. The alloy nanocrystallites also exhibit treatment process dependent characteristic changes in optical absorption and luminescence, and the optical data have been used to propose suitable energy level diagrams. A strong enhancement of blue excitonic emission and suppression of emission due to bulk and surface defects are seen after postsulphidation treatments of the multilayers containing alloy nanocrystallites. These studies have shown that the organic moieties encapsulating the Cdb>1-xb>Znb>xb>S nanocrystallites tend to restrict their growth and aggregation, while the presence of cadmium species in the organic matrix in proximity with the nanocrystallites is responsible for the passivation of surface defects as well as the reduction of bulk defects.