I want to maximize solar cell efficiency regardless of the sun's angle and so I've been looking at placing Compound Parabolic Concentrator (CPC) over the top of a high efficiency round solar cell. If I come up with a good design then I would like to try and manufacture some of them to see if I could start a small business for myself. I have 3 questions that I am working on, I will appreciate any advice. 1. Will it be most efficient to use CPCs placed over the top of highly-efficient round solar cells? Or will it add efficiency to place a Fresnel lens over the top of each CPC? or perhaps using a "DTIRC" (Dielectric Total Internal Reflection Concentrator) rather than a CPC? I could design the Fresnel lens to be a square that will refract all light into the round CPC directly below it so that I gain extra light, but I don't know if I will lose efficiency in other ways; e.g. it captures less sun angle than the CPC alone. 2. If I use a Fresnel lens can I design the prisms to filter out the IR frequency to reduce the heat of the solar cell? I've read that the cells become less efficient with heat. 3. What are the most efficient solar cells right now, especially the round shapped cells? A fourth question is regarding books on this subject; can you tell me any recommended books that would help me with the mathematics of the CPC and Fresnel designs; and also to learn about high efficiency designs in general. Thanks for your help.