Billabong launched earlier this year a wetsuit called the SG5 Surfing Wetsuit which uses Billabongs new solar mesh panel that acts the same way as a real solar panel - almost.

It does not convert sunlight into electrical energy as it is done in Photovoltaic solar cells but by absorbing the suns heat and trapping it within the cell structure of mesh making the wetsuits neoprene fabric 5-30% warmer than any nylon covered neoprene. 

It's an interesting material which I would like to know about more but I couldn't find any infos yet. If you have more details on how the solar fabric is build up please lave an note in the comments.