A New Dopant for Iron (II) Oxide-Based Solar Energy Conversion Devices: Enhanced Conductivity and Low Cost

Web Published:

Princeton Docket # 12-2823


Solar energy conversion devices include photovoltaics, photoelectrochemical cells and photocatalysts, which convert the energy of sunlight into electricity and produce fuels from carbon dioxide and water.  Different materials for making the solar energy conversion devices exhibit different energy conversion efficiencies and entail different costs.  Currently, the most prevalent semiconductor material used in the solar industry is (poly)crystalline silicon for photovoltaics, which requires an expensive purification process to obtain pure and defect-free materials.  First row transition metal oxides are much more affordable, because of their reasonable abundance, non-toxicity, ease of synthesis, and low cost for scaled-up manufacturing. However, a major setback of many transition metal oxides, which limits conversion efficiency, is low conductivity. 


Wüstite [i.e., iron (II) oxide] is of particular interest, as it is inexpensive and non-toxic, and has a band gap in the optimal range for absorbing solar energy.  However, wüstite suffers from thermodynamic instability in the bulk phase, but this disadvantage may be overcome by alloying with other stable oxides and potentially by nanostructuring. 


Using first-principles quantum mechanics calculations, researchers at Princeton University have discovered that adding small concentrations of an inexpensive additive (dopant) to Fe(II) metal oxide alloys can increase the number of charge carriers without adding charge trapping sites, and therefore can strongly enhance conductivity.  Thus, the new doped material should improve the photon-to-current/fuel conversion efficiency of solar energy conversion devices.



·        Enhanced Conductivity

·        Improved efficiency

·        Low cost

·        No toxicity



·        Semiconductors in photovoltaic cells

·        Electrodes in photoelectrochemical cells

·        Photocatalysts for fuel production


Faculty Inventor

Emily Ann Carter is Gerhard R. Andlinger Professor in Energy and the Environment and Professor of Mechanical and Aerospace Engineering & Applied and Computational Mathematics at Princeton University.   She is also the Founding Director of the Andlinger Center for Energy and the Environment at Princeton University.  Professor Carter's primary research lies along the interface of chemistry, materials science, applied physics, and applied mathematics.  Much of her work focuses on predicting the behavior of materials, analyzing properties of materials on the atomic level and then using that information to inform models at higher length scales for a comprehensive view of materials behavior. She has received many honors for her work, including election to the International Academy of Quantum Molecular Science (2009), the National Academy of Sciences (2008), and the American Academy of Arts and Sciences (2008).


Intellectual Property status


Patent protection is pending.


Princeton is seeking to identify appropriate partners for the further development and commercialization of this technology.




Michael Tyerech

Princeton University Office of Technology Licensing

609-258-6762   tyerech@princeton.edu


Laurie Bagley

Princeton University Office of Technology Licensing

609-258-5579   lbagley@princeton.edu


Patent Information:
For Information, Contact:
Chris Wright
Head of Technology Transfer
Princeton University
Emily Carter
Maytal Toroker
solar cell