Inverted Organic Solar Cells Fabricated with Room-Temperature-deposited Transparent Multilayer Electrodes

We investigated the electrical, optical, and structural properties of Al-doped ZnO (AZO)/Ag/AZO and indium gallium zinc oxide (IGZO)/Ag/IGZO multilayer films, and the performance of inverted organic solar cells (OSCs) fabricated with Sn-doped indium oxide (ITO), AZO/Ag/AZO, and IGZO/Ag/IGZO electrodes. Even though deposited at room temperature, AZO/Ag/AZO (36 nm/19 nm/36 nm) and IGZO/Ag/IGZO (39 nm/19 nm/39 nm) multilayer films showed sheet resistances of 4.1 and 4.2 Omega/sq, resistivities of 3.3 x 10(-5) and 4.1 x 10(-5) Omega cm, and transmittances of 93 and 88% at 550 nm, respectively. Figures of merit (FOMs) were obtained to be 99.9 and 49.9 x 10(-3) Omega(-1) for the AZO/Ag/AZO and IGZO/Ag/IGZO films, respectively. Inverted OSCs fabricated using the as-deposited AZO/Ag/AZO and IGZO/Ag/IGZO electrodes produced power conversion efficiencies (PCEs) of 2.4 and 2.6%, respectively, while that with high-temperature annealed ITO electrode gave a PCE of 3.2%.