Electrophotographic charging devices that can be used to charge or discharge, for example, a receptor in the electrophotographic process are provided. According to various embodiments, the exemplary charging devices can include a coronode disposed opposing and spaced apart from a receptor, and a plurality of nanostructures, wherein each of the plurality of nanostructures has an end, edge, or side in electrical contact with the coronode. The exemplary charging devices including the nanostructures can use less power, i.e. voltage and/or current than conventional charging devices and produce a reduced amount of oxidizing agents, such as, ozone and NO.sub.x. The nanostructures can serve to increase the intensity of the local electric fields for more efficient charge generation at reduced voltages.