Cohesion and device reliability in organic bulk heterojunction photovoltaic cells
KAUST Grant NumberKUS-C1-015-21
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AbstractThe fracture resistance of P3HT:PC 60BM-based photovoltaic devices are characterized using quantitative adhesion and cohesion metrologies that allow identification of the weakest layer or interface in the device structure. We demonstrate that the phase separated bulk heterojunction layer is the weakest layer and report quantitative cohesion values which ranged from ∼1 to 20 J m -2. The effects of layer thickness, composition, and annealing treatments on layer cohesion are investigated. Using depth profiling and X-ray photoelectron spectroscopy on the resulting fracture surfaces, we examine the gradient of molecular components through the thickness of the bulk heterojunction layer. Finally, using atomic force microscopy we show how the topography of the failure path is related to buckling of the metal electrode and how it develops with annealing. The research provides new insights on how the molecular design, structure and composition affect the cohesive properties of organic photovoltaics. © 2011 Elsevier B.V. All rights reserved.
CitationBrand V, Bruner C, Dauskardt RH (2012) Cohesion and device reliability in organic bulk heterojunction photovoltaic cells. Solar Energy Materials and Solar Cells 99: 182–189. Available: http://dx.doi.org/10.1016/j.solmat.2011.11.035.
SponsorsThis work was partly supported by the Director, Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division of the U.S. Department of Energy, under contract no. DE-FG02-07ER46391 and by the Center for Advanced Molecular Photovoltaics (CAMP) supported by King Abdullah University of Science and Technology (KAUST) under award no. KUS-C1-015-21.