Tunable plasmon resonances in two-dimensional molybdenum oxide nanoflakes

Tunable plasmon resonances in suspended 2D molybdenum oxide flakes are demonstrated. The 2D configuration generates a large depolarization factor and the presence of ultra-doping produces visible-light plasmon resonances. The ultra-doping process is conducted by reducing the semiconducting 2D MoO 3 flakes using simulated solar irradiation. The generated plasmon resonances can be controlled by the doping levels and the flakes' lateral dimensions, as well as by exposure to a model protein.