A quartz crystal microbalance (QCM) sensor includes a crystal plate, a buffer layer, and an electrode. The crystal plate has a first surface and a second surface. The second surface is opposite the first surface. The buffer layer includes a first buffer layer and a second buffer layer. The first buffer layer is disposed on the first surface of the crystal plate, the second buffer layer is disposed on the second surface of the crystal plate. The electrode includes a first electrode and a second electrode. The first electrode is disposed on the first buffer layer. The second electrode is disposed on the second buffer layer. The electrode includes at least one of titanium, scandium, beryllium, cobalt, yttrium, zirconium, technetium, ruthenium, lanthanum, cerium, praseodymium, neodymium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, lutetium, hafnium, rhenium, osmium, americium, curium, berkelium, and californium.