ZnO/Ag/ZnO Transparent Conductor Film And Modified ZnO Electron Transport Layer In Organic Solar Cells Application

As a kind of green renewable energy, solar energy has attracted great attention due to the double pressures of traditional energy reserve gradual depletion and environmental pollution caused by petrochemical energy. Photovoltaic power generation is a kind of effective way of using solar energy, and shows great potential instead of traditional energy. The silicon solar cells have developed a relatively mature photovoltaic technology, and fully realized industrialization application. However, the higher cost of silicon solar cells limits their widespread application. Organic solar cells have great advantage such as light weight, flexibility and low-cost and have reached the eve of commercial application with the breakthrough 10% of power conversion efficiency (PCE).From the purpose of enhanced PCE and the stability of organic photovoltaic cells (OPVs), the performances of OPVs based on regioregular poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methylester (PCBM) blended film were investigated. In this thesis, we primarily studied the characteristics of OPVs by modification of interface, and developed ZnO/Ag/ZnO transparent conductive film and its application in OPVs.(1) The performance of organic solar cells was investigated using soluble polyetherimide (PEI) and solution-processed ZnO nanoparticles as electron transport/exaction layer. The thickness of PEI was adjusted by changing concentration and spin-coating speed.(2) Using PEI-, LiF- and Au/LiF- modified ZnO as electron transport/extraction layers, the performance of OPVs can further be improved by optimizing the thickness of modified layer. The interface contact properties, morphologies and optical properties of electron transport layers are characteristic by uv-visible spectra, scanning electron microscope, fluorescence emission spectrum and ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy. Using an optimized Au/LiF-modified ZnO as an electron transport layer, the PCE of OPVs was improved 40% than that of OPVs with only ZnO layer. Less than 50% loss PCE of OPVs with LiF-modified ZnO layer are observed after aging one year at the ambient atmosphere without encapsulation, indicating OPVs with LiF modified ZnO compared to pure ZnO layer have better stability.(3) Multilayer transparent oxide thin films of ZnO/Ag/ZnO were fabricated by magnetron sputtering, which have sheet resistance as low as 5 ohm/sq and more than 80% transmittance at 400-700nm. The influence of plasmonic effects on the performance of OPVs is investigated by adjusted the thickness of the upper ZnO layer.