NOVELTY - A photovoltaic device (100) comprises an absorber layer (116) containing grains separated by grain boundaries, where at least one layer is disposed over the absorber layer. The grain boundaries are perpendicular to the layer disposed over absorber layer. The grains have a median grain diameter of less than 1 micrometer. The layer other than absorber layer is a window layer (114) and a back contact layer (118). The grain boundaries have a higher active dopant concentration when compared to dopant concentration in the grains. The grain boundaries comprise an active dopant.    USE - As a photovoltaic device (claimed), particularly solar cell.    ADVANTAGE - The absorber layer has controlled grain boundary doping and hence results in higher open circuit voltage (Voc) and improved device efficiency.    DETAILED DESCRIPTION - A photovoltaic device (100) comprises an absorber layer (116) containing grains separated by grain boundaries, where at least one layer is disposed over the absorber layer, and grain boundaries are perpendicular to the layer disposed over the absorber layer. The grains have a median grain diameter of less than 1 micrometer; and are columnar. The layer other than absorber layer is a window layer (114) and a back contact layer (118). The grain boundaries have a higher active dopant concentration when compared to dopant concentration in the grains. The grain boundaries comprise an active dopant. The active dopant density in the grain boundaries is sufficient to make the grain boundaries a type opposite to or same as the type of the grains. The grains and the grain boundaries both are p-type and n-type semiconductor. An INDEPENDENT CLAIM is included for preparation of the photovoltaic device involving providing absorber layer in photovoltaic device, where the grains are deposited using at least one technique selected from close-space sublimation, vapor transport deposition, ion-assisted physical vapor deposition, radio frequency or pulsed magnetron sputtering, and electrochemical bath deposition.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a photovoltaic device.    Photovoltaic device (100)    Substrate (110)    Front contact layer (112)    Adjacent window layer (114)    Absorber layer (116)    Adjacent back contact layer (118)    Metal layer (122)