title: Colloidal Nanoparticles for Intermediate Band Solar Cells.
abstract: The Intermediate Band (IB) solar cell concept is a promising idea to transcend the Shockley-Queisser limit. Using the results of first-principles calculations, we propose that colloidal nanoparticles (CNPs) are a viable and efficient platform for the implementation of the IB solar cell concept. We focused on CdSe CNPs and we showed that intragap states present in the isolated CNPs with reconstructed surfaces combine to form an IB in arrays of CNPs, which is well separated from the valence and conduction band edges. We demonstrated that optical transitions to and from the IB are active. We also showed that the IB can be electron doped in a solution, e.g., by decamethylcobaltocene, thus activating an IB-induced absorption process. Our results, together with the recent report of a nearly 10% efficient CNP solar cell, indicate that colloidal nanoparticle intermediate band solar cells are a promising platform to overcome the Shockley-Queisser limit.
authors.affiliation: †Department of Physics, University of California, Davis, California 95616, United States.|‡Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.
authors.forename: Márton
authors.initials: M
authors.lastname: Vörös
authors.affiliation: ‡Institute for Molecular Engineering, University of Chicago, Chicago, Illinois 60637, United States.|#Argonne National Laboratory, Lemont, Illinois 60439, United States.
authors.forename: Giulia
authors.initials: G
authors.lastname: Galli
authors.affiliation: †Department of Physics, University of California, Davis, California 95616, United States.
authors.forename: Gergely T
authors.initials: GT
authors.lastname: Zimanyi
keywords: absorption; density functional theory; doping; intermediate band; nanocrystal; nanoparticle solid; solar cell