Research

Overview | Semiconductors | Catalysts | Protection | Structures | Surfaces | Devices | Systems | Sensors

Our research spans from single materials to fully integrated, operational devices and focuses on solving present-day issues in energy and chemical sensing by controlling interactions between light, semiconductors, catalysts, and liquids.

Scanning electron micrograph (left) and electron backscatter diffraction image (right) of polycrystalline cuprous oxide (CU₂O).¹

Discover

We are discovering new semiconductors based on Earth-abundant elements, specifically materials capable of absorbing a significant portion of the visible spectrum.

We are discovering new catalysts for fuel-forming reactions, specifically the reduction of carbon dioxide and water to carbon-based fuels.  We are also discovering new catalysts for the oxidation of acidic water to oxygen gas.

Integrate

A silicon microwire array integrated with a nickel-molybdenum catalyst (highlighted purple, right) and titanium dioxide light-scattering particles.²

We are integrating semiconductors with catalysts and protective coatings to enable the efficient and stable operation of the light-absorbing components of solar fuels devices.  We align the devices we develop with the physical and technoeconomic requirements and constraints of full systems.

We are developing bottom-up and top-down approaches to making three-dimensionally structured semiconductors in order to optimize their absorption of light.

We are controlling the structure at the surfaces of semiconductors to control chemical reactivity and to improve the energy-conversion efficiency of devices.

Demonstrate

An integrated solar fuels device that produces separated product streams of hydrogen and oxygen gases from alkaline water and sunlight.³

We are building devices which convert the energy from sunlight into stored energy in the form of fuels or into electricity.

Detect

We are building sensors and discovering materials that enable inexpensive low-power detection of vapors.

References

1. Xiang, C. X.; Kimball, G. M.; Grimm, R. L.; Brunschwig, B. S.; Atwater, H. A.; Lewis, N. S., 820 mV open-circuit voltages from Cu₂O/CH₃CN junctions. Energy Environ. Sci. 2011, 4 (4), 1311-1318.
2. Shaner, M. R.; McKone, J. R.; Gray, H. B.; Lewis, N. S., Functional integration of Ni-Mo electrocatalysts with Si microwire array photocathodes to simultaneously achieve high fill factors and light-limited photocurrent densities for solar-driven hydrogen evolution. Energy Environ. Sci. 2015, 8 (10), 2977-2984.
3. Verlage, E.; Hu, S.; Liu, R.; Jones, R. J. R.; Sun, K.; Xiang, C.; Lewis, N.; Atwater, H. A., A monolithically integrated, intrinsically safe, 10% efficient, solar-driven water-splitting system based on active, stable earth-abundant electrocatalysts in conjunction with tandem III-V light absorbers protected by amorphous TiO₂ films. Energy Environ. Sci. 2015, 8, 3166-3172.

_{by Kimberly Papadantonakis, June 2016.}