). The resulting distance to graphene z of 15.3 nm is obtained using the 50% energy transfer distance d. By combining both, the 2D position and the distance to graphene z, a single fluorophore is localized in 3D with a precision of 1.9 nm in lateral and 0.3 nm in axial dimensions with moderate photon count rates of 1000 photons .
The precision in z is, on the one hand, determined by the precision of the fluorescence lifetime estimation, on the other hand, dependent on the slope of the graphene energy transfer relation hence on the absolute distance to graphene z . To evaluate the dependency of the absolute distance to graphene z on the precision, fluorophores were placed at different heights using DNA origami nanopositioners . Close to the 50% quenching distance d, GET reaches axial precisions of <0.3 nm at moderate photon number of 2000 photons per localization outperforming the xy precision of pMINFLUX nanoscopy which is at 1–2 nm. At higher distances to graphene of around 30 nm, the axial GET precision matches the lateral precision of pMINFLUX.