Ultrasensitive Gas Sensor of Mixed‐dimensional Heterostructures Combining Borophene and BC₂N Quantum Dots: Enhanced Detection through Binary Cooperative Effects

The emergence of mixed-dimensional van der Waals heterostructures has inspired worldwide interests in recent years, opening up new avenues for potential nanotechnology applications. Herein, we proposed a mixed-dimensional heterostructure composed of borophene sheets and BC₂N quantum dots. The gas sensing performance of the heterostructure was evaluated through a combination of theoretical calculations and experimental methods. Specifically, first-principles calculation results show that NO₂ is the most strongly interacting molecule and induces the largest amount of charge transfer between the molecule and the heterostructure, suggesting exceptional sensitivity and selectivity of the heterostructure to NO₂ gas. Following the theoretical insights, a borophene-BC₂N heterostructure gas sensor was developed and its gas detection abilities were assessed with exposure to various gases at room temperature. Remarkably, this sensor displayed a sensitivity of 1170 % to 30 ppm NO₂ and remain a high sensitivity of 108 % even to 0.2 ppm NO₂. These results highlight borophene-BC₂N heterostructure as a superior NO₂ gas sensor, demonstrating enhanced sensing via BC₂N quantum dots and integrated theoretical-experimental approaches.