High energy-resolution electron energy loss spectroscopy and near infrared absorption study of cesium tungsten bronze and lanthanum hexaboride

Cs_0.33WO₃ nanoparticles exhibit strong localized surface plasmon resonance (LSPR), making them effective at absorbing near-infrared (NIR) light. However, effectively tuning the optical absorption of Cs_0.33WO₃ in the critical NIR range of 800–1000 nm has remained a major challenge. In this study, we employ aberration-corrected electron microscopy to conduct high-resolution electron energy loss spectroscopy (EELS) on both Cs_0.33WO₃ and LaB₆ nanoparticles, reveal that the surface plasmon resonance in LaB₆ nanoparticles occurs at a higher energy than in Cs_0.33WO₃, allowing LaB₆ to absorb NIR light at shorter wavelengths. Based on this, we successfully adjusted the absorption characteristics of Cs_0.33WO₃ in the range of 800–1000 nm by utilizing the synergistic LSPR tuning of LaB₆ nanoparticles.