Emily Carter: Solar energy conversion devices

Thursday, Nov 29, 2012

Solar energy has the potential to reduce our use of nonrenewable fuels, but issues of cost, efficiency and durability pose problems. Several materials that could address these issues are central to the work of Emily Carter, the Gerhard R. Andlinger Professor in Energy and the Environment and founding director of the Andlinger Center for Energy and the Environment, which will be housed in a new laboratory complex (represented as a model in the photo) set to open in 2015.

Carter is researching materials that can act as photocatalysts, which use light to modify the rates of chemical reactions. She also is investigating materials for use in devices like photovoltaic and photoelectrochemical cells, which use light to produce electricity and fuel. Carter hopes that her team’s findings can be applied to the design of cheaper, more efficient and longer lasting solar and fuel cells.

Carter is focusing on creating these devices using materials called first-row transition metal oxides, which are cheap, abundant and resilient. Because these metals have low conductivity, Carter and her team are experimenting with elements to enhance the metals’ useful properties.

One transition metal oxide is hematite, a harder yet more brittle form of iron. Carter and her research team showed that doping hematite with manganese, cobalt or nickel can improve its ability as a water oxidation catalyst.  Another iron oxide, wustite, can be thermally stabilized using zinc oxide or nickel oxide.  Adding these materials, as well as adding zinc oxide to manganese oxide, can also increase the amount of light that can be absorbed, a major benefit when building solar cells.  Adding small quantities of certain elements to these oxides, as well as to cuprous oxide, can improve their conductivity. 

In addition, Carter’s research suggests that the durability of fuel cells can be greatly improved by adding certain elements to the nickel-zirconia anode material used currently.