State of the art photovoltaics exhibiting conversion efficiency in excess of 30% (1-sun) utilize epitaxially grown multijunction III-V materials. Increasing photovoltaic efficiency is critically important to the space power, and more recently, the terrestrial concentrator PV communitiesThe use of nanostructured materials within photovoltaic devices can enable improved efficiency, potentially in excess of the Shockley-Queisser limit. The addition of nanostructures such as quantum dots (QDs) to photovoltaic devices allows one to extend the absorption spectrum of the solar cell and "tune" the bandgap to the spectral conditions. Multi-junction (MJ) solar cells would benefit from the additional short-circuit current within the middle current-limiting (In)GaAs cell via QD spectral tuning. While QD tuning is a potentially direct approach to increased efficiency of MJ solar cells, it has been reported that significant improvements can be achieved using QDs to form an intermediate band within the bandgap of a suitable matrix.We will discuss the potential for QD photovoltaic devices and examine the challenges associated with multi-junction device growth with the inclusion of quantum dot arrays. GaAs p-i-n solar cells, with and without InAs QD superlattices are used to demonstrate the potential benefits of QDs. The unique challenges associated with the characterization of this type of device will also be presented. Using strain-balanced Stranski-Krastanov QD formation, we have demonstrated sub-gap photon collection and increased current in QD-enhanced GaAs solar cells containing up to 100 periods. Finally, we will discuss the opportunities that these devices hold for high photovoltaic conversion efficiency.