Table 1. Parameters used in the nextnano simulation.

Temperature	298.15 K
Diamond size	3150 nm
Conduction band energies, diamond	7.35, 5.47, 5.47 eV
VBM	2.12	(m0), hh
	0.70	(m0), lh
	1.06	(m0), so
Dielectric constant	5.68
Doping: nitrogen (bulk)	50 p.p.b.*
Ionization energy, nitrogen	1.7 eV30
Ionization energy, NV−	2.58 eV
Electrolyte	10 mM K-PBS buffer, 50 mM KCl, pH7
Electrolyte size	150 nm
Grid size	Down to 0.1 nm at the diamond/electrolyte interface

*The higher nitrogen impurity level used in the simulations accounts for additional defects present in the diamond lattice.