Perovskite Lanthanum-Doped Barium Stannate: A Refractory Near-Zero-Index Material for High-Temperature Energy Harvesting Systems

초록

The recent interests in bridging intriguing optical phenomena and thermal energy management has led to the demonstration of controlling thermal radiation with epsilon-near-zero (ENZ) and the related near-zero-index (NZI) optical media. In particular, the manipulation of thermal emission using phononic ENZ and NZI materials has shown promise in mid-infrared radiative cooling systems operating under low-temperature environments (below 100 degrees C). However, the absence of NZI materials capable of withstanding high temperatures has limited the spectral extension of these advanced technologies to the near-infrared (NIR) regime. Herein, a perovskite conducting oxide, lanthanum-doped barium stannate (La:BaSnO3 [LBSO]), as a refractory NZI material well suited for engineering NIR thermal emission is proposed. This work focuses on the experimental demonstration of superior high-temperature stability (of at least 1000 degrees C) of LBSO films in air and its durability under intense UV-pulsed laser irradiation below peak power of 9 MW cm-2. Based on the low optical-loss in LBSO, a selective narrow-band thermal emission utilizing a metal-insulator-metal (MIM) Fabry-Perot nanocavity consisting of LBSO films as metallic component is demonstrated. This study shows that LBSO is an ideal candidate as a refractory NZI component for thermal energy conversion operating at high temperatures in air and under strong light irradiations. Recent research has explored optical phenomena for thermal energy management using near-zero-index (NZI) materials. A perovskite oxide, La:BaSnO3 (LBSO), as a high-temperature NZI material for near-infrared thermal emission is introduced. LBSO exhibits stability at 1000 degrees C and resistance to intense UV laser. Using LBSO in a metal-insulator-metal nanocavity, selective narrow-band thermal emission, promising for high-temperature energy conversion, is achieved.image

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