Electrochemiluminescence from CdS Nanocrystals@Carbon Dots Composite Film
胡佳杰 南京晓庄学院, 南京市新型功能材料重点实验室, 南京 211171  
朱媛 南京晓庄学院, 南京市新型功能材料重点实验室, 南京 211171  
宋华菊 南京晓庄学院, 南京市新型功能材料重点实验室, 南京 211171  
王颖 南京晓庄学院, 南京市新型功能材料重点实验室, 南京 211171  
单云 南京晓庄学院, 南京市新型功能材料重点实验室, 南京 211171 
摘要: 采用热解柠檬酸法制备碳点(CDs),并将之与表面无包裹剂的CdS纳米晶(CdS NCs)超声复合制备CdS纳米晶@碳点(CdS NCs@CDs)复合物。研究了复合物膜阴极电致化学发光(ECL),探讨了CDs对CdS纳米晶膜ECL增强的机理。CDs分散性良好、尺寸在1.5~4 nm之间;与粒径约为4 nm的CdS纳米晶按体积比2∶3复合后,在360 nm光激发下复合物具有最强的荧光发射且表现为CDs的荧光。同时,复合物膜产生归属于激发态CdS纳米晶的最强的ECL发射,且ECL发光峰起置电势正移至-1.05 V。复合物膜的ECL发射是pH依赖的,在pH值为6时,复合物膜具有最大的ECL强度,为CdS纳米晶膜ECL强度的19倍。这种ECL增强源于CDs能束缚大量电子产生局域电场从而促进近邻CdS纳米晶激发态的形成与弛豫。
关键词: 半导体    纳米粒子  复合物  电致化学发光
基金项目: 国家自然科学基金(No.21872071,21375067)和江苏省自然科学基金(No.BK20161117)资助项目。
Abstract: Carbon dots (CDs) were prepared by pyrolysis of citric acid and composited with uncapped CdS nanocrystals (NCs) via ultrasonication to obtain CdS NCs@CDs composite. The cathodic electrochemiluminescence (ECL) from CdS NCs@CDs composite film was studied, and the mechanism underlying the ECL enhancement of CdS NCs film by CDs as well. The results showed that CDs were well dispersive and of 1.5~4 nm in diameter. When the volume ratio of CDs to CdS NCs with averagely size of 4 nm was 2:3, the CdS NCs@CDs composite showed the strongest photoluminescence (PL) which originated from CDs under excitation of 360 nm. Simultaneously, the composite film generated the strongest ECL emission ascribed to excited CdS NCs. The composite film had a more positive set on potential (-1.05 V) for ECL generation. ECL emission of the composite film was pH dependent with the maximum ECL emission occurring at pH=6, meanwhile ECL was 19 times larger than that of CdS NCs film. This ECL enhancement was possibly because a large number of electrons can be trapped in CDs to generate localized electric field that facilitates formation and relaxation of excited states of neighboring CdS NCs.
Keywords: semiconductors  carbon  nanoparticles  composite  electrochemiluminescence
投稿时间:2019-09-18 修订日期:2019-11-11
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