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.