Electrochemical modulation of fluorescence of nitrogen vacancy centers in nanodiamonds for voltage sensing applications

Abstract

The nitrogen vacancy (NV) color center in diamond has been used to sense environmental variables such as temperature and electric and magnetic fields. Most sensing protocols depend on the optically detectable magnetic resonance of the negatively charged NV- spin state. As such, fluctuations in the NV charge state present a challenge for NV- spin-based sensing. This thesis discusses the electrochemical modulation of NV charge state and fluorescence as the basis for an alternative sensing scheme. An externally applied electrochemical potential shifts the occupation probabilities of the NV in each charge state, which manifest as changes in NV fluorescence intensity and emission spectra. In this thesis, the voltage dependence of fluorescence in high pressure high temperature nanodiamonds is demonstrated in an electrochemical cell. Following this, the mechanisms for NV response to externally applied electrical bias are investigated in other electrochemical cell morphologies, capacitors, and interdigitated electrode arrays. Finally, a design of an optical microscope setup for future studies of NV sensing in nanodiamond is outlined.