Page 95 - Mirjam-Theelen-Degradation-of-CIGS-solar-cells

Experimental information

3.1 Introduction

The main goal of this thesis is to obtain better understanding about the long term
stability of CIGS solar cells and modules and to use this knowledge to optimise CIGS
solar cells and modules regarding their stability. As described in chapter 2, CIGS cells
and modules often fail due to exposure to moisture and elevated temperatures.
Furthermore, it was observed that light as well as electrical loads influence the
behaviour of CIGS cells, although these effects are not always detrimental.
Therefore, a setup has been designed in which we have exposed CIGS solar cells and
modules to humidity, elevated temperatures and illumination, while the illumination
also allows in-situ monitoring of the samples (Figure 3.1). The setup has been used
for various types of studies, aimed at a better understanding of the performance
and the degradation of CIGS solar cells and modules. The results of the degradation
experiments as obtained with this setup can be found in chapter 7. Furthermore, the
setup has been used to determine temperature dependency (chapter 4).
In this chapter, the CIGS solar cells as prepared for this setup and the setup itself
are described. Furthermore, the theory used in order to determine the solar cell
parameters in this setup is included.

(a) (b)

Computer
Solar cells
with light
and
temperature
Keithley sensors
for Multiplexer Climate
IV curves chamber

Figure 3.1:
(a) Photograph of the hybrid degradation setup (climate chamber plus illumination grid) (b) Schematic overview of the
hybrid degradation setup including the measurement system.

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