Solar Fuels
Sunlight is an abundant renewable energy resource. However, there is a large mismatch between the availability of sunlight and demand for electricity. This requires efficient energy storage to enable large-scale power generation using photovoltaic solar panels. Photoelectrochemical (PEC) cells use semiconductors to convert energy from the sun into chemical fuel, which can be stored and used on demand. These solar-fuel generators have the potential to supply carbon-neutral renewable energy on the terawatt scale.
Water-Splitting Prototype
Light Management Using Nano-Cones
Above is a schematic of our Solar Water-Splitting Device. With water and sunlight as the only inputs, the standalone device produces oxygen (O2) and hydrogen (H2) gas. The hydrogen can then be stored and used to drive a fuel cell to create on-demand energy.
Recent developments at the Joint Center for Artificial Photosynthesis (JCAP) have created an exciting opportunity for the construction of stable and highly efficient solar-fuel generators. In our device we use an electronically conductive or “leaky” TiO2 film grown by atomic layer deposition (ALD) and topped with a nickel oxide electrocatalyst to stabilize materials like silicon and gallium arsenide (GaAs) for water electrolysis in alkaline conditions.
In my current project I am experimenting with surface structures to maximize light absorption in our device. By modeling these structures using finite-difference time-domain (FDTD) simulations, I am able to design nanocones that act as wave-guides for incoming solar radiation, funneling light into the semiconductor and avoiding the metal-coated surface.
MY RESEARCH
Harvesting sunlight to make hydrogen fuel using earth abundant materials.
When combined with an optimized anti-reflection coating, these dielectric nanocones will transmit more than 95% of the boradband solar spectrum (400-1100 nm) with a surface catalyst covering 60% of the device, leading to higher device efficiency and longer stability.
