LOSSES DUE TO POLYCRYSTALLINITY IN THIN-FILM SOLAR-CELLS

The highest efficiency thin-film polycrystalline CuIn1-xGaxSe2 (CIGS) and CdTe solar cells are compared directly with crystalline Si and GaA s cells with similar respective bandgaps. The excess efficiency losses (6.3% for CIGS and 9.9% for CdTe) are quantitatively separated into e ight categories. In each case, the impact of polycrystallinity is eval uated, and the differential losses are identified as being directly at tributable to polycrystallinity or due to other causes. Approximately, two-thirds of the excess loss for polycrystalline cells is clearly du e to polycrystallinity. Thus, strategies such as grain passivation to reduce the impact of polycrystallinity should be examined, but at the same time conventional approaches for incremental improvement should r eceive attention. (C) 1998 Elsevier Science B.V. All rights reserved.