Synthesis and assembly of zinc hydroxide sulfate large flakes: Application in gas sensor based on a novel surface mount technology

Assembly of 2D materials into hierarchical architectures can produce films with high orientation and special properties. Most research focus on the nano-sized 2D flakes. In this report, zinc hydroxide sulfate (ZHS) large flakes with lateral size up to 410 μm were synthesized by hydrothermal treatment of ZnSO4·7H2O solution at 150 °C. The large ZHS flakes were then used as building blocks to assemble the oriented thick films with 63 μm thickness and tightly overlapped structure. Herein, we present one of its potential applications in the gas sensor. According to the TG-DTA analysis, the ZHS films were converted into ZnO thick films with 3D inter-linked particles and pores. Based on the obtained ZnO thick films, a novel surface mount technology was developed to fabricate ZnO gas sensor with low resistance, high sensitivity and fast response.