Advancement of applications related to information processing, telecommunication technologies, and light-based sensing relies on the development of infrared-active plasmonic materials. A new class of IR-relevant plasmonic material—spinel metal oxides (sp-MOs)—can address deficiencies of both metallic and semiconducting plasmonic nanomaterials in terms of control over spectral position, ease of fabrication, and environmental stability. As a result of their unusual structure, sp-MO systems support multiple doping modes for controlling free carrier density, which may afford unprecedented tunability in their plasmonic behavior. When paired with IR-active light-emitting semiconducting nanocrystals, i.e., quantum dots (QDs), sp-MOs may provide enhanced light emission by increasing radiative recombination rates through the well-known Purcell enhancement effect.<br/>Here, we show for the first time that magnetite, a sp-MO comprising iron in two oxidation states, can afford plasmonic behavior over 450 nm in the infrared. Furthermore, we demonstrate that through synthetic control over doping, crystal size, and nanocrystal heterostructure the plasmonic response can be deterministically tuned. We use electronic structure and Mie scattering theory-based modeling in combination with our direct experimental observations to establish the synthesis-structure/composition-functionality correlations underpinning both electronic behavior and the plasmonic response. Finally, we conclusively demonstrate that it is possible to achieve plasmonic-enhanced emission from IR-emitting QDs with an enhancement factor surpassing those achieved for emitters in the visible range using conventional noble metal plasmonic nanocrystals.

Plasmonic spinel oxide nanocrystals afford Purcell-enhanced emission in the infrared

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.