Ultrahigh-Sensitivity and Damage-Free Detection of Single Nanometer-Sized Particle

In the past decades, various methods, such as chemical sensing, X-ray screening, and spectroscopy, have been employed to detect explosives for environmental protection and national public security. However, achieving ultrahigh sensitivity for detection, which is crucial for some practical applications, remains challenging. This study employs scanning transmission electron microscopy and electron energy loss spectroscopy (STEM-EELS) to detect individual ∼200 nm explosive nanoparticles of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). The vibrational modes of HMX were acquired for each single nanoparticle under the aloof STEM-EELS mode, which ensures damage-free detection. Detailed comparisons with Raman and infrared spectra validate the acquired data's origin. This work highlights STEM-EELS as an effective tool in explosives detection, offering ultrahigh sensitivity, damage-free, and nanometer spatial resolution, with potential applications in environmental protection, public security, and criminal investigations.