Fabrication of PEDs using various nanomaterials, stencils, and ambient filtration. (A) The top stencil was laminated to a filter paper to create a patterned paper. (B) SWCNTs were first deposited onto the patterned area. Different bottom stencils were then placed beneath the SWCNT-laden paper, followed by filtration of different metal nanoparticles to generate layers of (C) AuNPs (bottom stencil 1) and (D) AgNPs (bottom stencil 2) on designated areas on the paper. (E) Each paper contains four PEDs, which each contain (F) an AgNP pseudo-RE, an AuNP WE, and a AuNP CE. The RE is indicated by a box.