ITO-free low-cost organic solar cells with highly conductive poly(3,4 ethylenedioxythiophene): p-toluene sulfonate anodes

Indium tin oxide (ITO)-free organic solar cells were fabricated with highly conductive and transparent tosylate-doped poly(3,4-ethylenedioxythiophene: p-toluene sulfonate) (PEDOT:PTS) anodes of various thicknesses that were prepared by the vapor-phase oxidative polymerization of EDOT using Fe(PTS)3 as an oxidant. Both solution-processable layers – PEDOT:PSS and photoactive P3HT:PCBM – were spin coated. The anodes transmittance and conductivity varied with thickness. Power conversion efficiency was maximized at 1.4%. The ITO-free organic solar cells photovoltaic characteristics are qualitatively compared with those of ITO-based organic solar cells to explore the possibility of replacing costly, vacuum-deposited ITO with highly conductive, patterned polymer films fabricated by inexpensive vapor-phase polymerization.

► ITO-free low cost solar cell. ► Easily processable polymer anode. ► Highly conductive PEDOT:PTS anode deposited by VPP method. ► Solar cell efficiency dependens on PEDOT:PTS thickness. ► PEDOT:PTS thickness is the main contributor to the optical intensity in the active layer.