Symposium B, Third-Generation and Emerging Solar-Cell Technologies, was held April 26 29 at the 2011 MRS Spring Meeting in San Francisco, California. Direct conversion of solar energy to electricity by photovoltaic (PV) devices is an important element of the portfolio of next-generation green power production. Although crystalline Si is currently the dominant material for making solar cells, new solar cells using thin films have been emerging due to their high competitiveness in cost reduction. Even more exotic materials have generated a great deal of excitement as in, for instance, assemblies composed of quantum dots and/or wires in which quantum confinement is used as a design parameter. Dye cells and organic PVs are also being pursued as affordable and low-cost paradigms. All such new and promising materials systems present challenges associated with the efficient absorption and collection of generated carriers, and the associated roadblocks stand between concept and practical implementation. This symposium proceedings volume represents the recent advances in all above mentioned areas.