Lee, Dongkyu Kim, Whi Dong Lee, Seokwon Bae, Wan Ki Lee, Sangheon Lee, Doh C. 2024-01-20T06:31:24Z 2024-01-20T06:31:24Z 2021-09-05 2015-08-11 0897-4756 https://pubs.kist.re.kr/handle/201004/125126 We report synthesis of PbSe nanorods (NRs) and PbSe/CdSe axial heterojunction NRs via direct Cd-to-Pb cation exchange in CdSe NRs. Use of suited ligand-cation combinations enables the cation exchange while keeping the nanomaterial morphology intact. For example, solvation of Cd2+ using oleylamine (OLA) allows for the cation exchange process, which would not be possible by using oleic acid instead of OLA. A mild cation exchange process, such as mixing Pb-oleate and OLA with CdSe NRs at 130 or 150 degrees C, results in anisotropic replacement of CdSe into PbSe along the < 0001 > direction of wurtzite CdSe, and a partial conversion leads to the formation of heterostructure NRs containing axial CdSe/PbSe heterojunctions. While the cation exchange proceeds at both tips of CdSe NRs, exchange appears to be faster on (000 (1) over bar) planes. Binding energy calculation based on density functional theory reveals that OLA binds strongly to the (000 (1) over bar) facet of CdSe NRs, leading to asymmetric cation exchange. This protocol to convert CdSe nanocrystals directly into PbSe broadens the design range of CdSe/PbSe heterojunction nanomaterials potentially with various morphologies because template CdSe nanocrystals can be prepared in different shapes via colloidal synthesis. English AMER CHEMICAL SOC CATION-EXCHANGE LIGAND-EXCHANGE SEMICONDUCTOR NANOCRYSTALS EXTINCTION COEFFICIENT PHASE-TRANSITION GROWTH KINETICS REACTIVITY CHEMISTRY WURTZITE Direct Cd-to-Pb Exchange of CdSe Nanorods into PbSe/CdSe Axial Heterojunction Nanorods Article 10.1021/acs.chemmater.5b01548 1 CHEMISTRY OF MATERIALS, v.27, no.15, pp.5295 - 5304 CHEMISTRY OF MATERIALS 27 15 5295 5304 scie scopus 000359499100018 2-s2.0-84939192140 Chemistry, Physical Materials Science, Multidisciplinary Chemistry Materials Science Article CATION-EXCHANGE LIGAND-EXCHANGE SEMICONDUCTOR NANOCRYSTALS EXTINCTION COEFFICIENT PHASE-TRANSITION GROWTH KINETICS REACTIVITY CHEMISTRY WURTZITE Surface Ligand Synthesis Quantum Dot Density functional theory