The use of near-zero index (NZI) materials for controlling radiative energy in thermal energy management has gained significant attention. However, conventional metal oxides suffer from notable changes in their optical properties at high temperatures, limiting their practicality in the near-infrared (NIR) range. This research investigates the potential of Lanthanum-doped Barium Stannate (LBSO) as a refractory NZI material suitable for high-temperature environments. By employing LBSO in a metal-insulator-metal (MIM) nano-cavity structure alongside Barium Titanate (BTO), a wavelength-selective thermal emitter was developed. The emitter exhibited impressive performance, with approximately 97% absorption at 2.2 µm, coinciding with the peak emission wavelength at 1000 ℃. Notably, the LBSO-based device demonstrated outstanding stability even under harsh high-temperature conditions.
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