A comparative study of La_1-xCa_xFeO₃ (0.4 ≤ x ≤ 0.8) pellets and La_0.6Ca_0.4FeO₃ thin films for the selective detection of low concentration SO₂ gas has been performed. The La_0.6Ca_0.4FeO₃ thin films exhibited superior gas sensing performance than La_1-xCa_xFeO₃ (0.4 ≤ x ≤ 0.8) pellets in terms of sensitivity, operating temperature, detection limit, response, and recovery time. The HRTEM images confirm the nanoparticle nature of the La_1-xCa_xFeO₃ (0.4 ≤ x ≤ 0.8) samples. The material crystallizes in the orthorhombic crystal system with the Pbnm space group. Further, occupancy refinement of neutron diffraction data indicates the presence of oxygen vacancies which was also supported by XPS analysis. Among the various compositions of La_1-xCa_xFeO₃ (0.4 ≤ x ≤ 0.8), the x = 0.4(La_0.6Ca_0.4FeO₃) was found to exhibit the best gas sensing performance and chosen for thin film preparation. The gas sensing studies of thin films, prepared by the DC magnetron sputtering method, confirm the enhanced gas sensitivity towards 3 ppm SO₂ gas at a low operating temperature of 120 °C. The selectivity studies show that La_1-xCa_xFeO₃ (0.4 ≤ x ≤ 0.8) preferentially detects SO₂ gas at the given operating condition over other gases such as CH₄, CO₂, and CO. The gas sensing mechanism and high sensitivity of the La_1-xCa_xFeO₃ sensor towards the detection of SO₂ gas were explained by DFT calculations which give evidence for the strong binding of SO₂ molecules on the 121 surface of the sensor.

已经进行了La _1-x Ca _x FeO ₃（0.4 <x <0.8）球团和La _0.6 Ca _0.4 FeO ₃薄膜的选择性研究，以选择性检测低浓度SO ₂气体。在灵敏度，工作温度，检测极限，响应和恢复时间方面，La _0.6 Ca _0.4 FeO ₃薄膜表现出比La _1-x Ca _x FeO ₃（0.4 <x <0.8）颗粒更好的气体传感性能。HRTEM图像证实了La _1-x Ca _x FeO ₃的纳米性质（0.4 <x <0.8）个样本。该材料在具有Pbnm空间群的正交晶体系统中结晶。此外，对中子衍射数据的占有率的细化表明氧空位的存在，这也得到了XPS分析的支持。在La _1-x Ca _x FeO ₃（0.4 <x <0.8）的各种组成中，发现x = 0.4（La _0.6 Ca _0.4 FeO ₃）表现出最佳的气敏性能，并被选择用于薄膜制备。通过直流磁控溅射方法制备的薄膜的气敏性研究证实，对3 ppm SO _2的气体敏感性增强气体在120°C的低工作温度下工作。选择性研究表明，La _1-x Ca _x FeO ₃（0.4 <x <0.8）在给定操作条件下比其他气体（例如CH ₄，CO ₂和CO ）优先检测SO ₂气体。通过DFT（密度泛函理论）计算解释了La _1-x Ca _x FeO ₃传感器对SO ₂气体检测的敏感性，这提供了SO ₂分子在传感器121平面表面上牢固结合的证据。表面。