A photovoltaic device is provided comprising an absorber layer, wherein the absorber layer comprises a plurality of grains separated by grain boundaries. At least one layer is disposed over the absorber layer. The absorber layer comprises grain boundaries that are substantially perpendicular to the at least one layer disposed over the absorber layer. The plurality of grains has a median grain diameter of less than 1 micrometer. Further, the grains are either p-type or n-type. The grain boundaries comprise an active dopant. The active dopant concentration in the grain boundaries is higher than the effective dopant concentration in the grains. The grains and grain boundaries may be of the same type or opposite type. Further, when the grain boundaries are n-type the bottom of the grain boundaries may be p-type. A method of making the absorber layer is also disclosed.