SSTE-4 Program Advanced Photovoltaic Cell Technologies: Ground Chamber Test Results

Plasma ground-testing results, obtained at the John H. Glenn Research Center National Plasma Interaction Facility, are presented for a number of thin-film photovoltaic cells. The cells represent a mix of promising new technologies identified by the Air Force Research Laboratory under the space science technology experiment (SSTE-4) Program. The current ground-testing efforts are aimed at characterizing both the performance and survivability of thin-film technologies in the harsh Low Earth Orbit space environment where they are intended to be flown. Measurements of parasitic currents and arc threshold voltages were performed in situ under strictly controlled charging conditions for both amorphous silicon (a-Si) and copper indium gallium selenide cells. Surface flashing on the large-area a-Si cells revealed that microdischarges in the dielectric surface do not appear to cause any apparent degradation to the cells. Catastrophic arc testing between adjacent cells resulted in no sustained arcs. Similar catastrophic arc tests between adjacent strings resulted in self-extinguished nonsustained arc extensions on time scales of approximately 100 mus in length. All cell efficiency measurements were performed in the Solar Cell Calibration Laboratory prior to plasma testing and then once again after the completion of the plasma tests.