Probing the Challenge of P‐Type Semiconductors in Long‐Chain VOC Detection: 3D Micro‐Flower Zinc Cobaltate Heterojunction Sensors

Abstract Tetradecane, a long‐chain alkane recently recognized as a volatile marker for early‐stage mildew detection in stored grains and as a reference material in hydrocarbon studies, presents significant challenges for detection due to its inherent low reactivity and substantial molecular size. This study reports the synthesis of a microflower‐like Fe@WO ₃ / ZnCo ₂ O ₄ heterostructure for effective tetradecane sensing. The Fe@WO ₃ / ZnCo ₂ O ₄ n‐p junctions demonstrated significant alterations in electrical conductivity upon exposure to tetradecane at room temperature. The sensor achieved a reasonable detection limit of 78.4 ppb and a rapid recovery time of 36 s. The remarkable sensing performance is attributed to the synergistic interactions among multiple heterojunction interfaces, doping‐induced active sites, the presence of oxygen vacancies, high‐energy crystallographic facets, reduced grain size, and enhanced crystallinity, as supported by density functional theory calculations and molecular dynamics simulations. This work identifies a promising candidate for the detection of distinct volatile organic compounds, warranting further exploration in agricultural and emission monitoring applications while addressing a critical gap in metal oxide semiconductor sensors for the detection of large‐molecule gases.