This Small Business Innovation Research Phase I project provides the lowest cost selective emitter (SE) for solar photovoltaics and will help lower costs towards grid parity. Selective emitter technology for solar cells has so far involved complex processes with at least two or more steps in addition to a standard solar cell process flow. Current SE processes also require increasing the number of grid lines on the front of the solar cell which results in light being blocked. The proposed self-aligned selective emitter (HSE) process represents the simplest, one-step approach to creating a selective emitter for n-type wafer based solar cells. This will be a high throughput process with a cost of less than $0.01/Wp. Efficiency increases in excess of 1% absolute are achievable unlike other selective emitter technologies which are limited to about 0.6% absolute efficiency increases.
The broader impact/commercial potential of this project has global, national, and local significance. The price of solar modules has decreased drastically over the past several years in response to technological improvements, manufacturing efficiencies and innovative balance-of-systems approaches. This in turn has created exponential market demand. As the price continues to drop, each incremental cost savings becomes more challenging. The proposed technology provides an elegant solution to reducing the cost of solar and is easy to implement for existing manufacturing lines. The production of HSE equipment would help domestic solar PV producers reach grid parity in additional markets. In the local community, an additional job will be created, and an undergraduate and four graduate students will be exposed to entrepreneurship, commercialization of federally funded research and cutting edge energy research. Additionally, collaboration with university professors will strengthen the ties to the surrounding community and help foster discussions about commercialization of academic research. Publications will be used to rapidly disseminate the results of this work and foster a deeper understanding of selective emitters and their role in photovoltaics.
The hydrogen super emitter (HSE) is a selective emitter for n-type silicon solar cells with none of the drawbacks. Traditionally, selective emitters require more silver (extra cost) and multiple additional processing steps in the middle of a manufacturing line (extra cost and complexity) which have severely limited market adoption. The HSE process overcomes both of these fatal flaws by actually reducing the amount of silver by 22% and occurring as a single step at the end of the manufacturing line. During this award we completed proof-of-concept for the HSE concept and demonstrated a remarkable 16% relative efficiency improvement on lab solar cells. This was possible by developing a deeper understanding of the interaction between hydrogen and dopant materials within the crystal lattice. This National Science Foundation Phase I award enabled us to apply for, and subsequently receive, the highly competitive SunShot Incubator award from the Department of Energy (DOE). A business plan was presented at numerous business launching competitions including the MIT Clean Energy Challenge sponsored by the DOE which resulted in a total of $317,000 in prizes to expedite commercialization. The work resulted in a research paper that will be presented at the 2014 Photovoltaic Specialists Conference in addition to two patents that were filed in the US & Taiwan in addition to a PCT filing. Two PhD level graduate students were involved in the work and were exposed to cutting edge R&D in an entrepreneurial environment.
