CIGSSe technology


South Africa is at the forefront of the development of new solar power technology. The breakthrough technology is the result of over 13 years of research by the University of Johannesburg's Professor Vivian Alberts.

His solar panels are made from a unique metal alloy that converts light into energy at a fraction of the usual cost; this will offer consumers a cheaper and highly efficient alternative to standard solar panels. Unlike standard solar panels that contain a 350 micron thick silicon layer, Alberts' panels make use of copper, indium, gallium, sulphur and selenium. The result is a revolutionary thin panel, approximately five microns thick (1/4 the size of a hair follicle).

Thin film solar modules also offer further advantages: the conversion of a broader light spectrum means that electricity is generated even under low light conditions. Due to the construction of the cells comparatively high yields can be obtained even under conditions of partial shadow. Improved temperature coefficients – which means lower loss of performance at high temperatures – thin film modules are especially suited to temperatures over 25 degrees Celsius.

In the first production step, a wafer-thin layer of molybdenum is applied to a glass pane. This layer forms the back contact of the cells. The actual semiconductor only emerges in subsequent process steps. For this, the precursor layer consisting of copper, indium and gallium is first applied.

These three elements are then chemically transformed in a diffusion process under a gaseous atmosphere containing sulphur and selenium. The result is a unique crystalline coating – the CIGSSe absorber layer. It guarantees the high performance level of our modules. The electrical serial connection of individual cells into a module is realised during the coating process by structuring individual layers. This structuring gives rise to the typical "pinstripe" design of the thin film modules. A German company has snatched up this new technology and will be developing it further. With a manufacturing plant scheduled for construction in Western Cape soon.

 Source: Johanna Solar Technology