Reducing the absorber layer thickness below 1 μm for a regular copper indium gallium di-selenide (CIGS) solar cell lowers the minimum quality requirements for the absorber layer due to shorter electron diffusion length. Additionally, it reduces material costs and production time. Yet, having such a thin absorber reduces the cell efficiency significantly. This is due to incomplete light absorption and high Molybdenum/CIGS rear-surface recombination [1]. The aim of this research is to implement some innovative rear surface modifications on a 430 nm thick CIGS absorber layer to reduce both these affects: an aluminium oxide passivation layer to reduce the back-surface recombination and point contact openings using nano-particles for electrical contact. The impact of the implementation of all these rear-surface modifications on the opto-electrical properties of the CIGS solar cell will be discussed and analyzed in this paper.

A 'hybrid' degradation setup, which allows the use of humidity, temperature and illumination as loads in order to accelerate degradation of solar cells and modules, has been designed and constructed. In this setup, the current voltage output of photovoltaic samples is automatically logged and the electrical parameters are calculated. This allows the study of the impact of illumination and damp heat induced degradation by in-situ monitoring. Additionally, this setup also allows the determination of temperature dependency of solar cells by a simple procedure.