<em>In Situ</em> Monitoring of the Accelerated Performance Degradation of Solar Cells and Modules: A Case Study for Cu(In,Ga)Se₂ Solar Cells

Abstract

The levelized cost of electricity (LCOE) of photovoltaic (PV) systems is determined by, among other factors, the PV module reliability. Better prediction of degradation mechanisms and prevention of module field failure can consequently decrease investment risks as well as increase the electricity yield. An improved knowledge level can for these reasons significantly decrease the total costs of PV electricity. In order to better understand and minimize the degradation of PV modules, the occurring degradation mechanisms and conditions should be identified. This should preferably happen under combined stresses, since modules in the field are also simultaneously exposed to multiple stress factors. Therefore, two 'Combined Stress test with in situ measurement' setups have been designed and constructed. These setups allow the simultaneous use of humidity, temperature, illumination, and electrical biases as independently controlled stress factors on solar cells and minimodules. The setups also allow real-time monitoring of the electrical properties of these samples. This protocol presents these setups and describes the experimental possibilities. Moreover, results obtained with these setups are also presented: various examples about the influence of both deposition and degradation conditions on the stability of thin film Cu(In,Ga)Se2 (CIGS) as well as Cu2ZnSnSe4 (CZTS) solar cells are described. Results on the temperature dependency of CIGS solar cells are also presented.

Material Property Changes in Defects Caused by Reverse Bias Exposure of CIGS Solar Cells

“…The layer stack of the CIGS solar cells used is: 1mm soda-lime glass, 500 nm DC-sputtered molybdenum, 2 µm coevaporated CIGS, 50 nm chemical bath deposited cadmium sulfide, 65 nm DC sputtered intrinsic zinc oxide, 1 or 2 µm DC sputtered aluminum doped zinc oxide and 60 nm thermally evaporated gold contacts to the sides. A detailed description of the cell design and fabrication procedure can be found in [7].…”

Propagation mechanism of reverse bias induced defects in Cu(In,Ga)Se2 solar cells

“…A schematic of the cell design is given in Figure 1. More information on the cell design and manufacturing proces can be found in previous work [10,11] and a description of the 3-stage CIGSe co-evaporation process is given by Couzinie-Devy et al [12]. For this study ten samples from three different CIGSe deposition runs were used.…”

Tailoring Morphology Compatibility and Device Stability by Adding PBDTTPD-COOH as Third Component to Fullerene-Based Polymer Solar Cells

“…To investigate the impact of the third component on the device stability, accelerated long-term stability tests are carried out for the reference devices and for the optimized devices of each series. , The I – V measurements are performed periodically on the device for around 4 h under illumination in ambient conditions. The temporal evolution of the photovoltaic parameters J SC , V OC , FF, and PCE is extracted from the I – V measurements and plotted in Figure .…”