Sterling engine solar is really cool. 50% efficiency. Solar panels will never be that high. Looks cool too. 

https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Fi.ytimg.com%2Fvi%2FCDCTANU8Tfk%2Fmaxresdefault.jpg&f=1&nofb=1&ipt=0bba9910e9affeaa6d3f4a35c29c5fbbb3d58174117bc0249186f55fa7ade9e0&ipo=images