Zinc oxide nanorod arrays hydrothermally grown on a highly conductive polymer for inverted polymer solar cells

We present fully solution processable hybrid electrodes comprising highly conductive poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) layers and hydrothermally grown zinc oxide nanorods. These electrodes exhibit conductivities of about 1400 S/cm and a transmittance of more than 80%. By incorporating these electrodes into inverted polymer photovoltaic devices, power conversion efficiencies of 1.6% are achieved. Charge carrier lifetime measurements by means of impedance spectroscopy indicate an improved charge carrier extraction from the device upon the incorporation of the nanorod array.

► A precursor based seed layer for hydrothermally grown ZnO nanorods is presented. ► ZnO nanorods are grown on a highly conductive printable polymer layer. ► Polymer/nanorods composite layers are highly transparent and conductive (1400 S/cm) ► Incorporation of these hybrid electrodes into 1.6%-efficient polymer solar cells is demonstrated. ► Improved charge transport properties due to the ZnO nanorods are verified by means of impedance spectroscopy.