Fig. 6From: Imaging of polymer:fullerene bulk-heterojunctions in a scanning electron microscope: methodology aspects and nanomorphology by correlative SEM and STEMa Relation between specimen thickness at contrast inversion and primary electron energy for PTB7 and PC71BM derived from measurements and MC simulations using different scattering cross-sections. The inset in a shows a top-view SEM image of FIB-prepared TEM lamella with a constant thickness of about 184 nm. b–d HAADF–STEM cross-section images of the sample with stacked pure PC71BM and PTB7 layers using a FIB-prepared lamella with a constant sample thickness taken at b 8 keV, c 16.5 keV, and d 30 keV. The grey line in a marks the electron energy (16.5 keV) at contrast inversion according to c and the derived lamella thickness. Images in b–d are post-processed according to the procedure described in “Materials and methods” sectionBack to article page