X maxn silicon drift detector

Three microliters of AuNP solution were deposited onto freshly glow discharged 200 mesh nickel TEM grids coated with a carbon-stabilized formvar film (Electron Microscopy Sciences, Hatfield, USA). The AuNPs adsorbed onto the film surface for 5 min after which the excess solution was wicked away using filter paper. The grids were then washed in quick succession in three droplets of MilliQ water. Excess water was removed using filter paper and the grids allowed to air dry.
TEM was performed utilizing a FEI Tecnai T20 G2 (Thermo Fisher Scientific, Waltham, USA) operating at 200 kV located at the Center for Electron Nanoscopy at DTU. Both low and high magnification images, as well as energy dispersive X-ray spectra (EDS), were acquired for each AuNP sample. Images were acquired using a CCD camera equipped with Digital Micrograph (Gatan, Pleasanton, USA), and EDS spectra were acquired using a X-max^N Silicon Drift Detector (Oxford Instruments, Abingdon, UK). Image analysis was performed using Fiji analysis software 69 (link). Nanoparticle diameter was determined using the 'analyze particle function' of Fiji to obtain an area for each nanoparticle, making sure not to include nanoparticles that were overlapping in the measurements, and converting this value to a diameter assuming a spherical nanoparticle. A minimum of 250 nanoparticles were measured for each sample.