The Staebler-Wronski Effect is the name given to a phenomenon in which a charge accumulator has an increased capacity to conduct electricity. This phenomenon is a crucial factor in the design of modern solar panels. However, the Staebler-Wronski effect has not been studied in great detail, so many questions remain. This article examines this effect and some of the challenges involved in using it in solar panels.
Amorphous Silicon Based Solar Cells
Amorphous silicon based solar cells have attracted considerable attention. This material has a high optical bandgap and is therefore particularly suited for use in semiconductor devices. However, it has been noted that the Staebler-Wronski Effect (SWE) may cause degradation in the performance of these cells.
This effect is induced by the light that is absorbed by amorphous silicon. The amount of amorphous silicon degradation depends on the intensity of exposure, the temperature coefficient, and the manufacturing process. It affects amorphous silicon based solar panels in the first 100 hours. Afterwards, it stabilizes. This effect is dependent on the alloying elements and is also affected by the hydrogen content in the amorphous silicon.
Alloys of amorphous silicon with Group VIa elements, such as selenium and sulfur, are particularly suitable for photovoltaic applications. These alloys are typically formed on solid-state substrates, such as quartz, stainless steel, and titanium. Amorphous silicon with Group VIa elements exhibits excellent resistance to the Staebler-Wronski effect, which makes them suitable for high efficiency photovoltaic cells.
Amorphous silicon based solar cells are one of the most advanced thin-film technologies in the field of energy conversion. They can be produced using a variety of processes known in the art.
The initial performance of an amorphous silicon based solar cell is very good, but the performance degrades as the light intensity increases. This degradation is mainly caused by the Staebler-Wronski influence. At first, the degradation is rapid. The reduction in the cell’s efficiency is related to the thickness of the intrinsic layer. It is also affected by the dangling bond density.
Challenges of A-Si Solar Panels
Amorphous silicon photovoltaic devices are an emerging technology that promise to improve efficiency. Thin film silicon photovoltaic devices are based on amorphous silicon (a-Si), a material that is allotropic and non-crystalline. There are several challenges that may prevent the commercialization of upscale a-Si technologies.
First, there are high wafer quality requirements. Such high requirements increase the production costs of such devices. A second challenge is the cost of processing waste modules.
In addition, the conversion efficiency of a-Si solar cells decreases 10-30% during the first six months of operation. This is a result of Staebler-Wronski degradation. This degradation is reversible after annealing.
To avoid the depletion of minority carriers, a doped layer is used. However, doped layers have poor electronic properties and have a modest lifetime. Therefore, a buffer layer is added, such as a SiC or a-Si:H layer. This layer can improve the passivation effect and Voc values.
Thin film silicon solar cells are manufactured in two different configurations: substrate and superstrate. The former is used in single-junction and multi-junction solar cells, while the latter is used in double-junction and triple-junction devices.
Multi-junctions provide advantages over single-junction devices, such as the ability to extend the absorbed light spectrum. They also allow for the use of a variety of absorber materials.