3.46 μm mid-infrared emission from lead-free double perovskite fluorine glass and multi-wavelength array gas real-time monitoring applications in hydrogen energy

The current industrial hydrogen production processes generate hydrogen gas containing various impurities, including hydrogen chloride and carbon dioxide, which may affect its usability. Optical temperature sensing plays a crucial role in hydrogen energy research, with particular emphasis on the importance of light sources emitting wavelengths that match the absorption wavelengths of the target gas. For instance, the 3.4 μm wavelength corresponds to the absorption of HCl gas, yet the literature lacks reports on light source materials that match this particular requirement. This study focuses on exploring a series of infrared light source arrays that emit wavelengths matching the absorption wavelengths of gases, specifically emphasizing the 3.4 μm wavelength as it aligns with HCl gas absorption. There have been limited instances of luminescent durations surpassing 3 μm reported. In this work, the Cs₂AgIn_1-xTm_xCl₆-ZBLAY perovskite fluoride glass emits mid-infrared luminescence at 3.46 μm, a key finding as it coincides with the distinctive absorption peaks of HCl gas at the same 3.4 μm wavelength. First-principles calculations were performed to enhance understanding of the density of states and electronic energy band structure of Cs₂AgIn_1-xTm_xCl₆. Cs₂AgIn_1-xTm_xCl₆-ZBLAY perovskite fluoride glass, indicating its potential as a future material for mid-infrared emission. It is non-toxic and emits mid-infrared light at a wavelength of 3.46 μm, which is expected to be useful in infrared imaging, biomedicine, gas detection and other applications. Therefore, a real-time gas-monitoring device with a multi-wavelength array using Cs₂AgIn_1-xTm_xCl₆-ZBLAY,Cs₂AgIn_1-xEr_xCl₆-ZBLAN, and ZBLAN: Ho has been designed.