Synthesis and characterization of CuInS2 quantum dots

• Main Authors: Yang, Yue-Ru, 楊岳儒
• Other Authors: Chiang, Ray-Kuang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/93752322324879672489

碩士 === 遠東科技大學 === 材料科學與工程研究所 === 102 === This study is divided into three parts. The first part is about the synthesis of copper indium sulfide (CIS) quantum dots (QDs) with different Cu/In ratios of 1/1, 1/2, 1/4, 1/8. A mixture of Cu precursor (CuI or Cu acetate), indium acetate (In(Ac)3), and 1-dodecanethiol (DDT) is heated to 110-120℃ to form a mixed metal thiolate complex, which is further decomposed at 230℃ to form CIS NPs with a chalcopyrite-type structure. The second part is about the high-band gap material coating reaction, which allows the NPs to form core/shell NPs that can decrease the surface trap states and restrict the exciton in the core area to have a higher quantum yield. The coating material is either ZnS (Eg = 3.8 ev) or CdS (Eg =2.42 ev). The reaction temperature is about 240℃ to allow the precursor to decompose and diffuse into the core, in which a blue shift in PL and a higher QY is obtained. To further increase the QY, a double coating step is performed. In all these reactions, under a selected optimal Cu/In ratio (1/4), the PL efficiency is monitored by the PL peak areas with reaction time to reach the bright PL point. The third part is about applying the CIS QDs in white light LED. The CIS QDs with emission of 550~560 nm is selected and incorporated into a polymer matrix of PMMA co LMA to form a film. This film is combined with a blue LED light guide to emit a white light with CRI of 66.1%. After adding a red emitting thin film of NP, the CRI can improve to 85.5 %.