Interface Modification of ZnO-Based Inverted PTB7:PC71BM Organic Solar Cells by Cesium Stearate and Simultaneous Enhancement of Device Parameters
journal contributionposted on 05.05.2014, 00:00 by Guojie Wang, Tonggang Jiu, Gang Tang, Jun Li, Pandeng Li, Xiaojin Song, Fushen Lu, Junfeng Fang
We used cesium stearate (CsSt) to modify the interface of the electron-extracting contact in inverted organic solar cells. Surface microstructure, optical properties, and electrical characterization as well as exciton generation rate and dissociation probability were investigated to understand the impact of CsSt on the interface contact. The results indicated that by incorporation of CsSt, the surface morphology and energy level as well as conductivity of a zinc oxide (ZnO) film were improved. On the basis of the above properties, highly efficient inverted organic solar cells have been demonstrated by using a ZnO nanoparticle film and CsSt stacked bilayer structure as the cathode interfacial layer. The insertion of a CsSt layer between the ZnO film and active layer improved the electron extraction efficiency, and a high power conversion efficiency (PCE) of 8.69% was achieved. The PCE was improved by 20% as compared to the reference device using a ZnO-only electron extraction layer.
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dissociation probabilitysurface morphologyDevice ParametersWeinterface Modificationelectron extraction efficiencyreference devicebilayer structurecesium stearatePTBZnO filmPCEenergy levelpower conversion efficiencyexciton generation rateinterface contactSurface microstructurezinc oxideCesium StearateCsSt layerZnO nanoparticle filmSimultaneous Enhancement