Plasmon Resonances and Structures of Chalcogenlde Alloy Nanocrystals

摘要

Alloying on the nanoscale is a powerful chemical handle for tuning the structural,electronic, and optical properties through continuous composition variation. Here, we explore theimpact of alloying on the structural and optoelectronic properties of copper chalcogenidenanocrystals. Cuprous selenide-sulfide alloy nanocrystals were made hy the cation exchangereaction. The nanocrystals upon oxidation exhibit localized surface plasmon resonances. Thelocalized surface plasmon resonance frequency follows an anomalous trend as a function of the alloycomposition. Similar behavior is seen for the electrical properties of the alloy nanocrystals with markedly suppressed conductivitiesmeasured at the intermediate compositions. This anomalous behavior originates from the mixed-phase nature of individualnanocrystals at the intermediate compositions and structural disorder resulting from the drastic difference in anionic sublatticestructures of cuprous selenide and cuprous sulfide phases. This study shows that alloy nanocrystals produced by the cation exchangereaction can have complex intraparticle structures and properties.