Mn‐Doped CuO Nanostructure Films Based Gas Sensor for High Sensitive and Selective Formaldehyde Detection at a Room Temperature

Abstract The development of an efficient gas‐sensing materials is crucial for applications in healthcare, industry, environmental monitoring, and agriculture. In this study, Mn‐doped CuO thin films were synthesized and evaluated for their gas‐sensing properties. The fabricated films exhibited a monoclinic CuO structure with (002) and (111) orientations, and their morphology reveals a uniform, spherical‐like crystalline distribution. Mn doping adjusts the optical bandgap from 2.11 eV to 2.03 eV. Compared with pure, 3% Mn‐doped CuO‐based sensor demonstrated a high response value of 82% to 20 ppm formaldehyde at room temperature with swift response and recovery times of 9 and 36 s, respectively. The high sensitivity and stability of these sensors make Mn‐doped CuO films a promising candidate for practical gas detection applications.