Supercritical Synthesis and Characterization of Graphene鈥揚bS Quantum Dots Composite with Enhanced Photovoltaic Properties

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• 作者：Ahmad Tayyebi ; Mohammad Mahdi Tavakoli ; Mohammad Outokesh ; Azizollah Shafiekhani ; Abdolreza (Arash) Simchi
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2015
• 出版时间：August 5, 2015
• 年：2015
• 卷：54
• 期：30
• 页码：7382-7392
• 全文大小：684K
• ISSN：1520-5045

文摘

Lead sulfide quantum dots (PbS QDs) were decorated onto a graphene surface in a semi-core鈥搒hell structure using supercritical ethanol. The temperature of ethanol played significant role in controlling size and agglomeration of QDs as well as the extent of reduction of graphene. Average size of the QDs was estimated by transmission electron microscopy to be around 3.96 nm and by quantum models to be about 4.34 nm. PbS QDs prepared at 330 掳C were of high purity, and the yield was 99%. Instrumental and chemical analyses demonstrated formation of a strong bond between PbS QDs and graphene, through a Pb鈥揙鈥揅 bridge. UV and photoluminescence measurements along with theoretical considerations revealed that integration of PbS QDs with graphene results in efficient separation of the electron鈥揾ole, thus enhancing photo 鈫?electric energy conversion. This outcome was further evidenced by comparison of performance of PbS/G in a solar cell, with the performance of pristine PbS QDs.