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

Abstract 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 BC 2 N 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 NO 2 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 NO 2 gas. Following the theoretical insights, a borophene‐BC 2 N 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 NO 2 and remain a high sensitivity of 108 % even to 0.2 ppm NO 2 . These results highlight borophene‐BC 2 N heterostructure as a superior NO 2 gas sensor, demonstrating enhanced sensing via BC 2 N quantum dots and integrated theoretical‐experimental approaches.