Image analysis of polycrystalline solar cells and modeling of intergranular and transgranular cracking

An innovative image analysis technique is proposed to process real solar cell pictures, identify grains and grain boundaries in polycrystalline silicon, and finally generate finite element meshes. Using a modified intrinsic cohesive zone model approach to avoid mesh dependency, nonlinear finite element simulations show how grain boundaries and silicon bulk properties influence the crack pattern. Numerical results demonstrate a prevalence of transgranular over intergranular cracking for similar interface fracture properties of grains and grain boundaries, in general agreement with the experimental observation.