We consider the scattering of incident plane-wave electrons from a defect in a crystal modeled by the time-harmonic Schrodinger equation. While the defect potential is localized, the far-field potential is periodic, unlike standard free-space scattering problems. Previous work on the Schrodinger equation has been almost entirely in free-space conditions; a few works on crystals have been in onedimension. We construct absorbing boundary conditions for this problem using perfectly matched layers in a tight-binding formulation. Using the example of a point defect in graphene, we examine the efficiency and convergence of the proposed absorbing boundary condition.