Enhanced photovoltaic conversion of ZnO/PANI/NiOx heterostructure devices with ZnO nanorod array

Abstract

An n-i-p type of organic-inorganic hybrid bifacial solar cells was constructed with a ZnO/polyaniline/NiO x heterostructure, in which vertically aligned ZnO nanorods (ZnONd) were synthesized by a facile electrochemical deposition process and act as an electron-transport layer. Semitransparent p-type semiconducting NiO x films were utilized as a hole-transport layer. Devices based on the ZnONd considerably outperform those employing ZnO thin films. The contact and electrical properties of NiO x can be carefully tuned through controlling the deposition parameters as well as surface treatments. Intimate contact between NiO x with PANI, created by in situ electrochemical polymerization, greatly improves the charge movement. Furthermore, an O2-plasma treatment of the NiO x film has a significant impact on the performance of polyaniline/ZnONd hybrid photovoltaic devices, reflected by the enhancement in the fill-factor and efficiency. The power conversion efficiency of the ZnONd/PANI/NiO x device under the optimized O2 plasma condition can reach up to 2.79% under AM1.5 illumination.