Hydrogen from Light

Conventional renewable energy systems (wind, solar, hydro and geothermal) often suffer from low energy conversion rate so that the size needs to be prohibitively big, high initial investment, low return on investment and low lifetime. These energy systems are also often not suitable for all-purpose and everywhere applications as installation needs significant time and resource, and the generated electricity must be carried from the place of generation to the place of application. Practically, both consumers and energy suppliers need more efficient and cost-effective clean energy alternatives by disruptive and distributed technologies which can generate their own energy and to the fixed and competitive price of electricity than conventional sources. Hydrogen is a clean fuel that, when consumed in a fuel cell, produces only water, electricity, and heat (zero emission fuel). Hydrogen and fuel cells can provide energy for use in diverse applications, including distributed or combined-heat-and-power; backup power; systems for storing and enabling renewable energy; portable power; auxiliary power for transport vehicles. The major limitation in this case is lower solar to hydrogen conversion (STH) efficiency and higher payback period that arise from factors such as an inability to utilize full spectrum of solar energy and rapid recombination rate of photogenerated charge carriers and use of costly materials. Hence, the overall objective of this project is to harvest chemical energy in the form of hydrogen from solar energy by developing techniques for efficient solar energy absorption, photogenerated charge carrier separation, transport and transfer of photogenerated carriers for photochemical reactions to produce hydrogen and oxygen: efficiently and cost-effectively. The target STH efficiency is ~10% and payback period is <10 years.