Fabrication of inverted bulk heterojunction organic solar cells basedon conjugated P3HT:PCBM using various thicknesses of ZnO bufferlayer

摘要

Recently, there has been tremendous progress among the researchers all over the world in the devel-opment of polymer-based organic solar cells as a clean and safe energy source. Besides, it has alsoattracted a great attention due to its inexpensive manufacturing cost and environment-friendly energyconversion capability. However, they still have low efficiency and the unstable because organic mate-rials are easily oxidized by humidity and UV light under the atmosphere environment. The objectiveof this study was to investigate the effects of different thickness of the ZnO buffer layer on the gen-eral performance of the bulk heterojunction organic solar cell devices with configuration indium tinoxide/zinc oxide buffer layer/poly(3-hexylthiophene):[6,6]-phenyl-C61butyric acid methyl ester/gold(ITO/ZnO/P3HT:PCBM/Au). ZnO film acts as a protection layer to prevent the interface of photoactivelayer by UV light from the oxidation and to reduce the energy barrier for easily transferring electronbetween collecting electrode and the LUMO level of the organic acceptor. Also, ZnO film block holes inP3HT from being recombined with electrons in collecting electrode. It is observed that the power conver-sion efficiency is significantly dependent on the thickness of the buffer layer. The solar cell performanceof a short-circuit current density of 1.599 mA/cm2, an open-circuit voltage of 119 mV and a fill factor of20.85%, with a power conversion efficiency of about 0.0432% under AM 1.5 illumination (100 mW/cm2)is obtained when the thickness of the buffer layer is optimized.