TY - JOUR
T1 - Direct Cd-to-Pb Exchange of CdSe Nanorods into PbSe/CdSe Axial Heterojunction Nanorods
AU - Lee, Dongkyu
AU - Kim, Whi Dong
AU - Lee, Seokwon
AU - Bae, Wan Ki
AU - Lee, Sangheon
AU - Lee, Doh C.
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/8/11
Y1 - 2015/8/11
N2 - 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 °C, results in anisotropic replacement of CdSe into PbSe along the <0001a> 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 (0001¯) planes. Binding energy calculation based on density functional theory reveals that OLA binds strongly to the (0001¯) 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.
AB - 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 °C, results in anisotropic replacement of CdSe into PbSe along the <0001a> 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 (0001¯) planes. Binding energy calculation based on density functional theory reveals that OLA binds strongly to the (0001¯) 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.
UR - http://www.scopus.com/inward/record.url?scp=84939192140&partnerID=8YFLogxK
U2 - 10.1021/acs.chemmater.5b01548
DO - 10.1021/acs.chemmater.5b01548
M3 - Article
AN - SCOPUS:84939192140
SN - 0897-4756
VL - 27
SP - 5295
EP - 5304
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 15
ER -