Apparatuses and methods for preparing carbon nanostructure sheets are provided. The apparatuses may include a casting body including a substrate configured to move along a first direction, a slurry reservoir configured to contain a slurry, a dispenser connected to the slurry reservoir and configured to dispense the slurry onto a surface of the substrate and a doctoring member that extends in a second direction traversing the first direction and that is positioned above the surface of the substrate. The slurry may include carbon nanostructures, and/or one or more functional materials. The doctoring member may be spaced apart from the surface of the substrate by a predetermined distance.