This report summarizes the in-house and subcontracted research and development (R and D) activities under the National Center for Photovoltaics (NCPV) from October 1, 1997 through September 30, 1998 (FY 1998). The NCPV is part of the U.S. Department of Energy's (DOE's) National Photovoltaics Program, as described in the DOE National Photovoltaics Program Plan for 1996-2000. The mission of the DOE National Photovoltaics Program is to make PV a significant part of the domestic economy--as an industry and as an energy resource. The two primary goals of the national program are to (1) maintain the U.S. industry's world leadership in research and technology development and (2) help the U.S. industry remain a major, profitable force in the world market. The NCPV provides leadership and support to the national program toward achieving its mission and goals.