Nilotpal Kapuria1, Michele Conroy,2,3* Vasily A Lebedev1, Temilade Esther Adegoke1, Yu Zhang2, Ibrahim Saana Amiinu1, Ursel Bangert, Andreu Cabot4,* Shalini Singh,1* and Kevin M Ryan1*
1Department of Chemical Sciences and Bernal Institute, University of Limerick, V94T9PX Limerick, Ireland.
2Department of Physics and Energy and Bernal Institute, University of Limerick, V94T9PX Limerick, Ireland
3Department of Materials, Royal School of Mines, Imperial College London, London SW7 2AZ, United Kingdom
4Catalonia Institute for Energy Research IREC, 08930 Barcelona, Spain; ICREA, 08010 Barcelona
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Link to Paper:
Direct colloidal synthesis of multinary metal chalcogenide nanocrystals typically develops dynamically from the binary metal chalcogenide nanocrystals with the subsequent incorporation of additional metal cations from solution during the growth process. Metal seeding of binary and multinary chalcogenides is also established, although the seed is solely a catalyst for nanocrystal nucleation and the metal from the seed has never been exploited as active alloying nuclei. Here we form colloidal Cu−Bi−Zn−S nanorods (NRs) from Bi-seeded Cu2−xS heterostructures. The evolution of these homogeneously alloyed NRs is driven by the dissolution of the Bi-rich seed and recrystallization of the Cu-rich stem into a transitional segment, followed by the incorporation of Zn2+ to form the quaternary Cu−Bi−Zn−S composition. The present study also reveals that the variation of Zn concentration in the NRs modulates the aspect ratio and affects the nature of the majority charge carriers. The NRs exhibit promising thermoelectric properties with very low thermal conductivity values of 0.45 and 0.65 W/mK at 775 and 605 K, respectively, for Zn-poor and Zn-rich NRs. This study highlights the potential of metal seed alloying as a direct growth route to achieving homogeneously alloyed NRs compositions that are not possible by conventional direct methods or by postsynthetic transformations.