Hypersonic Shockwave Robustness in Infrared Plasmonic Doped Metal Oxide Nanocrystal Cubes: Implications for High-Speed Ballistics Transport Applications

We report that, in doped metal oxide nanocrystal cubes, the infrared plasmonic absorption optical property is robust under exposure to repeated hypersonic shockwaves at Mach 6.2. Fluorine–tin co-doped indium oxide (F,Sn:In2O3) shock-exposed nanocrystals demonstrate morphological and optical property robustness, including infrared localized surface plasmonic resonance absorption at 4164 cm–1 (2401 nm) and cubic shape retention at 14 nm in size. Surface oxidation from reduced indium to oxidated (In2O3) and hydroxylated (In-OH) indium states is observed. Yet, free electron carrier concentration at 8.18 × 1020 cm–3, estimated to be 2245 electrons per nanocrystal, is retained in the nanocrystal core at 15 shock cycles. This demonstrates preservation of the plasmonic absorption property under an extreme hypersonic shock environment. We expect that doped infrared plasmonic metal oxides can serve as a keystone for nanomaterial scientists in potential applications for high performance infrared optical filters and sensor devices in surface exposed hypersonic aerospace vehicles.