The symposia that have been combined to compose this volume - Symposium B: 'Thin Film Compound Semiconductor Photovoltaics', Symposium C: 'Perovskite Solar Cells', Symposium D: 'Organic-Based Photovoltaics', and Symposium E: 'Advance Solar Cells-Components to Systems' - were held from April 6-10 at the 2015 MRS Spring Meeting in San Francisco, California.