Hydrothermal synthesis and gas-sensing properties of ultrathin hexagonal ZnO nanosheets

Gas-sensing performances are often enhanced significantly once size of the sensing materials approaches a critical value of 15 nm. Here, we synthesize, by a simple hydrothermal method, ultrathin hexagonal ZnO nanosheets with a thickness of 17 nm. The cetyltrimethylammonium bromide is found to play a critical role in producing such unique hexagonal ZnO nanosheets, and a possible growth mechanism is proposed. The as-prepared ultrathin nanosheets exhibit excellent gas-sensing properties to formaldehyde gas at optimal temperature of 350 C under concentration of 50 ppm, rendering the ultrathin nanosheets promising for the on-site detection of formaldehyde.