Local analysis of the efficiency of solar cells based on dark lock-in thermography imaging

Abstract

The dark forward current of solar cells strongly influences their energy conversion efficiency. If lock-in thermography is applied to a solar cell in the dark with electrical current pulse excitation, it images any inhomogeneity of the current flow in this cell. Since also the illuminated characteristic may be derived from the dark characteristic, the detailed local analysis of the dark characteristic enables the prediction of local efficiency parameters. This contribution describes the physical basics of this procedure and shows a typical example of such a local efficiency analysis.