You might have watched a different version of their ad than any of the ones we saw. Rayton makes the claim in the media we’ve seen that their cells are 25% more efficient because they use pure silicon. Our best guess is that they are referring to the greater efficiency of monocrystalline silicon to polycrystalline silicon. Monocrystalline silicon can be found in many solar modules such as those made by Sunpower and is indeed ~25% more efficient. Thanks for your comment!