SOLTERRA RENEWABLE TECHNOLOGIES

  

Objectives

Solterra Renewable Technologies (SRT) plans to market a thin-film photovoltaic cell incorporating its proprietary quantum dot semiconductors. SRT will utilize our exclusive license from University of Arizona Regents for Dr. Ghassan Jabbour’s patented printing technology in the production of our solar cells. Our objective is to become the first solar cell manufacturer to be able to offer a solar electricity solution that competes on a non-subsidized basis with the price of retail electricity in key markets in North America, Europe, the Middle East and Asia.

Cost Savings

Solterra will manufacture very low cost solar cells using a thin layer of quantum dot semiconductor material, rather than silicon chips, to convert sunlight into electricity. Cost savings are achieved three ways: our proprietary quantum dots are more efficient and cheaper than existing quantum dots, our thin-film materials are lower cost than silicon materials and substrates and our solar cell manufacturing processes use low cost printing technologies. Overall LCOE – Lifetime Cost of Enterprise – including startup costs, production, efficiency, recycling and other LCOE factors will prove the efficacy of our quantum dot thin-film PV solar cells.

Potential Efficiency

Quantum dot technology has the potential to be the most efficient method of producing solar electricity. The Department of Energy’s National Renewable Energy Lab has reported 65% theoretical conversion efficiency for quantum dot solar cells.

Tetrapod CdSe quantum dots provide access to quantum effects that provide for greater power generation abilities and, therefore, greater efficiency per dollar. Using tetrapod quantum dots in a solar cell to create an intermediate band allows the harvesting of a much larger portion of the available solar spectrum, and prior research has shown that four-legged tetrapod quantum dots are many times more efficient at converting sunlight into electricity than regular quantum dots. Quantum dot solar cells have extremely high potential efficiency, having demonstrated the production of multiple excitons from a single electron. This phenomenon is the key to exponential increases in conversion efficiency. Quantum dot solar cells also have the ability to harvest light energy in the infrared and ultraviolet spectra leading to better low light collection efficiency and the potential to continue harvesting energy even when little or no visible light is present. Infrared sunlight accounts for 43% of the sun’s rays but silicon solar panels cannot convert this to energy and lose this valuable energy as waste heat.

Solterra’s tetrapod quantum dots can be formed into an ordered 3-D array including different sized IR and UV quantum dots. This 3-D array increases the likelihood that each ray of light impinging on a PV solar cell will cause electrons to flow within the cell and can increase the voltage of the solar device through Hot Electron (or Hot Carrier) Transport. Traditional semiconductors, no matter how well made, cannot match the size dimensions of quantum dots (2-10 nanometers), and thus cannot exploit the quantum effects that exist at such size dimensions.

Multiple Exciton Generation (MEG) is another effect that quantum dots can produce. Research has show that in a traditional solar cell each photon of light striking the cell yields one exciton. However, pioneering work by Dr. Nozik and NREL in Golden, Colorado has demonstrated that the absorption of a single photon by their quantum dots yielded - not one exciton as is usually the case, but three of them. When a photon strikes a quantum dot it can produce potentially 3 electrons, and some reports of up to 7 electrons have been published. The formation of multiple excitons per absorbed photon happens when the energy of the photon absorbed is far greater than the semiconductor band gap. This phenomenon does not readily occur in bulk semiconductors where the excess energy simply dissipates away as heat before it can cause other electron-hole pairs to form. In semi-conducting quantum dots, the rate of energy dissipation is significantly reduced, and the charge carriers are confined within a minute volume, thereby increasing their interactions and enhancing the probability for multiple excitons to form.

Solterra’s quantum dots can be prepared with a protective shell, which increases their stability and yields longer lasting solar cells without degradation in performance. This represents another advantage over traditional semiconductor devices, which do not have protective molecular shells to guard against the harmful effects of the sun, and therefore must be replaced more often, driving up material cost. By applying this proprietary low cost production technology to the manufacture of quantum dots and applying it to solar energy cells, the cost of solar-generated electricity is reduced to little more than grid price at today’s electricity prices.

Being Part of the Solution

Solterra believes that the manufacture of our thin film quantum dot solar cells can introduce a cost effective disruptive technology that can help accelerate the conversion from a fossil fuel dependent energy infrastructure to one based on renewable, carbon-neutral energy sources. All of our manufacturing processes, from QD synthesis to solar cell mass production use low temperatures, “greener” materials, less gas, less waste and heat product, and less energy in production than any solar cell product. We believe that our proposed products also can be a part of the solution to greenhouse gases and global warming.

See the Solterra Renewable Technologies Website for more information.