Since January 1993, Progress in Photovoltaics has published six monthly listings of the highest confirmed efficiencies for a range of photovoltaic cell and module technologies. 1–3By providing guidelines for inclusion of results into these tables, this not only provides an. . The conversion efficiency of a photovoltaic (PV) cell, or solar cell, is the percentage of the solar energy shining on a PV device that is converted into usable electricity. Improving this conversion efficiency is a key goal of research and helps make PV technologies cost-competitive with. . Solar-cell efficiency is the portion of energy in the form of sunlight that can be converted via photovoltaics into electricity by the solar cell. Guidelines for inclusion reviewed. An appendix describing temporary electrical contacting of large-area solar cells approaches and terminology is also included.