In this paper, a thin film plasmonic solar cell configuration employing a gap mode assisted periodic metal grating back layer is proposed and illustrated. Significant improvement in light absorption is observed due to the combined effect of gap mode excitation between metal surface and nanoparticle, and the excitation of waveguide modes due to periodic back metal reflector. With the proposed configuration, approximately 5.4% enhancement in absorption is observed when compared to a gap mode based planar metal layer configuration. (C) 2013 Elsevier B. V. All rights reserved.