PV cells have usually a blue or black colour. The reason for this is the normal choice of antireflection coating or the surface finish.

Colour of PV cells and modules can be altered by two methods namely:

1. By varying the thickness of the anti-reflection coating. So the colour does not need always to be blue. It can be silver-like, blue, bronze, gold, green, and magenta. It can even be a rainbow if the thickness varies gradually.

2. By using coloured and or screen-painted glass to cover or sandwich the PV cells. Even opaque glasses can be used for this purpose.

We perceive that a surface has one certain colour if that particular surface mainly reflects that colour. A blank uncoated Silicon surface will reflect nearly all the incident light therefore it gives us a silver-like appearance. On the other hand a surface with a black finish will hardly
reflect any colour therefore absorb maximum the incident light. This would be the ideal PV surface finish. An overview of possible colours is given in Figure 14. The typical cost for adding colour to cells is 2 to 3 times the price of normal cells (per cell). The colour will also result in a degradation of performance over normal cells of about 20%.!!

Figure 14: Example of various coloured solar modules by varying thickness of anti reflection coating of the cells. This is typically associated with the need to create a distinctive look either for security reasons or for architectural reasons [BP Solar, 2004]