Experimental Demonstration of Optically Determined Solar Cell Current Transport Efficiency Map

TL;DR

This paper experimentally validates a reciprocity relation for determining solar cell current transport efficiency using luminescence imaging, demonstrating its applicability under various conditions and identifying different series resistances affecting efficiency.

Contribution

It provides experimental evidence for a reciprocity relation to map current transport efficiency in solar cells, enabling non-invasive analysis under real-world conditions.

Findings

The reciprocity relation is experimentally validated.

Current transport efficiency varies with illumination and voltage.

Different series resistances contribute to efficiency losses.

Abstract

A recently suggested reciprocity relation states that the current transport efficiency from the junction to the cell terminal can be determined by differentiating luminescence images with respect to the terminal voltage. The validity of this relation is shown experimentally in this paper, by comparison with simultaneously measured electrical currents and simulations. Moreover, we verify that the method is applicable under various light concentrations and applied voltages, which allows us to investigate the cell in relevant conditions. Results evidence several kind of series resistances affecting the current transport efficiencies. We show that the relative contribution of those different resistances to the loss in current collection is a function of the illumination intensity.