Degenerately hydrogen doped molybdenum oxide nanodisks for ultrasensitive plasmonic biosensing

Plasmonic biosensors based on noble metals generally suffer from low sensitivities if the perturbation of refractive-index in the ambient is not significant. By contrast, the features of degenerately doped semiconductors offer new dimensions for plasmonic biosensing, by allowing charge-based detection. Here, this concept is demonstrated in plasmonic hydrogen doped molybdenum oxides (H x MoO 3 ), with the morphology of 2D nanodisks, using a representative enzymatic glucose sensing model. Based on the ultrahigh capacity of the molybdenum oxide nanodisks for accommodating H + , the plasmon resonance wavelengths of H x MoO 3 are shifted into visible-near-infrared wavelengths. These plasmonic features alter significantly as a function of the intercalated H + concentration. The facile H + deintercalation out of H x MoO 3 provides an exceptional sensitivity and fast kinetics to charge perturbations during enzymatic oxidation. The optimum sensing response is found at H 1.55 MoO 3 , achieving a detection limit of 2 × 10 -9 m at 410 nm, even when the biosensing platform is adapted into a light-emitting diode-photodetector setup. The performance is superior in comparison to all previously reported plasmonic enzymatic glucose sensors, providing a great opportunity in developing high performance biosensors.