Tailoring PEDOT:PSS polymer electrode for solution-processed inverted organic solar cells

Abstract

Conductivity and work function of the conductive polymer, poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), has been investigated for a top electrode of the solution-processed organic solar cells (OPV). It has been found that both conductivity and work function could be changed by adjusting the mixing ratio of different commercial grade PEDOT:PSS such as PH 1000 and AI 4083. A 2:1 vol ratio of PH 1000 and AI 4083 mixture provided the conductivity of 443 S/cm (corresponding sheet resistance (R-sh) of 260 Omega w/sq) and the work function of 5.09 eV. Therefore, this PEDOT:PSS mixture may work as both a hole transport layer (HTL) and anode electrode of the OPV. For verifying, all-solution-processed bulk heterojunction (BHJ) inverted OPVs were fabricated using developed PEDOT:PSS conductive polymers as both HTL and anode top electrode. Under the AM1.5G spectrum calibrated 100 mW/cm(2) illumination, fabricated all-solution-processed OPV provides a best photo-conversion efficiency (PCE) of 2.04% accounted from an open circuit voltage (Voc) of 576 mV, a short circuit current (Jsc) of 6.91 mA/cm(2), and a fill factor (FF) of 51.2%. In addition, the final OPV exhibits semitransparency due to no metal electrode on top and transparency of the conductive polymer.