A functional device includes a pair of electrodes 1 and 4 and a
macromolecular structure including a hole-conducting layer 5 and an
electron-conducting layer 2. The macromolecular structure includes a
first hyperbranched macromolecule and a second hyperbranched
macromolecule, at least one of the first hyperbranched macromolecule and
the second hyperbranched macromolecule has a hole conductivity or an
electron conductivity, one of the hole-conducting layer and the
electron-conducting layer includes one of the first hyperbranched
macromolecule and the second hyperbranched macromolecule, and the
macromolecular structure has a self-assembled structure formed by a
non-covalent interaction via the first hyperbranched macromolecule or the
second hyperbranched macromolecule in at least one of the hole-conducting
layer, the electron-conducting layer and the interface between the
hole-conducting layer and the electron-conducting layer.