Highly Conductive PEDOT: PSS Electrode Treated with Polyethylene Glycol for ITO-Free Polymer Solar Cells

We used polyethylene glycol (PEG) and enhanced the conductivity of PEDOT:PSS from 0.3 S cm-1 to 805 S cm-1 with only 2% PEG additive. The conductivity was further enhanced to 1100 S cm-1 by combining PEG and methanol treatment. PEG treated PEDOT:PSS films showed better phase separation between PEDOT and PSS with fiber like 3D PEDOT networks. The carrier concentration increased by three orders of magnitude after PEG treatment. ITO-free polymer solar cells with PEG treated PEDOT:PSS anodes were fabricated and optimized. Double layer PEDOT:PSS treated with 2% PEG200 anodes showed power conversion efficiency of 3.71% while and the ITO counterpart showed 3.73%.