Figure 2.

(A) The molecular structures of PTB7-F20 and PC₇₁BM; (B) the conventional device structure of PSCs without incorporating any Fe₃O₄ magnetic nanoparticels (MNPs); (C) the conventional device structure of PSCs incorporated with Fe₃O₄ MNPs and aligned by an external magnetostatic field; (D)–(F) the fabrication procedures of PSCs incorporated with Fe₃O₄ MNPs and aligned by an external magnetostatic field; (D) BHJ active layer incorporated with Fe₃O₄ MNPs was spin-coated on PEDOT:PSS coated ITO substrate; (E) a ferromagnet was suspend above the surface of BHJ composite incorporated with Fe₃O₄ MNPs layer. The magnetic intensity is ~30–40 G and the distance between the ferromagnet and BHJ composite layer is ~10 cm; (F) oriented Fe₃O₄ MNPs inside BHJ active layer by an external magnetostatic field. In pre-devices; (G) Drawing of partial enlargement of Fe₃O₄ MNP in (C), showing an antiparallel relation between the magnetic dipole (caused by the Fe₃O₄ crystal inside the particle) and electric dipole (caused by the difference of charge density between the inside Fe₃O₄ and outside organic coater).