Sunlight Photonics business concept

Here is the business concept behind Sunlight Photonics, a semi-finalist in the MIT $100k competition (the recently renamed version of the $50k competition):

The electricity generated by silicon-based solar cells is directly proportional to the amount of light they absorb (C. Kittel, 1986). However, silicon displays low absorption within the critical near-infrared region of the solar spectrum. As a result, one can either make a thin cell that absorbs very little of this light, decreasing efficiency, or a thick cell that absorbs more of this light, but requires more raw material (driving up costs).

We plan to build an R&D oriented firm that sells intellectual property which improves the efficiency of existing silicon-based solar cells. Its revenues will be based on licensing our IP to existing solar cell manufacturers. The IP includes device technology and expertise in the implementation of the device technology into standard solar cell manufacturing processes. We have performed a detailed calculation which shows that our current device technology can improve the efficiency of solar power generation by up to a factor of five in some parts of the near-infrared spectrum, and at least 20% overall compared to those cells which lack photonic crystals. Alternatively, we can use this improved efficiency to decrease the thickness of the solar cell dramatically, cutting down the amount of silicon used by as much as a factor of ten (cutting the biggest component of materials costs, silicon, by 90%), while retaining a similar level of efficiency as seen in current technology. This grating is projected to integrate well with preexisting photolithographic processing steps and should only lead to small increases in overall processing costs.