“…Owing to their advantages of high stability, simple instrumentation, label-free detection, and capacity for real-time monitoring, quartz crystal resonators have been applied in a variety of areas, for example, the frequency source of communication systems, 1) gas sensors [2][3][4][5] and biosensors. [6][7][8][9][10] Based on the mass loading effect, quartz crystal microbalances (QCMs) coated with water-absorbing materials, including graphene oxides, 11) nanodiamond film, 12) TiO 2 , 13) SnO 2 nanowires 14) and polydopamine/graphene oxide, 15) have been developed as sensitive humidity sensors.…”