A CuO-ZnO nanostructured p-n junction sensor for enhanced N-butanol detection

Herein, a novel CuO-ZnO nanostructured p-n junction composite is prepared via the hydrothermal method. It is composed of a ZnO two dimensional (2-D) porous nanosheet assembly and leaf-like 2-D CuO nanoplates. Then, its gas sensing performance toward n-butanol is studied. The 2-D/2-D CuOZnO composite sensor shows 2.7 times higher sensitivity than that of pure ZnO at 220 degrees C. Moreover, its response to n-butanol is 3.5-84 times higher than those for other target gases. This reveals an excellent selectivity toward n-butanol. Its detection limit for n-butanol is calculated to be 0.4 ppm, indicating a potential advantage in low concentration detection. The significant enhancement of the composite's sensing performance can be firstly attributed to the p-n junction, which brings electronic sensitization for the composite sensor. Moreover, the porous structure and the open 2-D/2-D heterostructure also contribute to the sensing performance of the composite. These allow the gas molecules to diffuse rapidly, making chemisorption and surface reactions on the p-n junction more easy.