Abstract
Prussian blue analogues (PBAs) have attracted increasing interest owing to their potential applications in various fields such as energy storage and conversion, neuromorphic computing, and magnetic switching. With a general formula of AxMN[MC(CN)6], they feature an open framework that provides abundant channels for diffusion of alkali metal ions A and allows flexible compositional control of transition metal ions MNand MC. The oxidation states of transition metal ions can be tuned by adjusting the amount (x) of alkali ions A. Here, we carried out density functional theory calculations combined with experimental measurements to investigate the effects of transition metal ions, alkali ions, and oxidation states on the electronic properties of PBAs. Our calculations found that the band gaps of PBAs can be tuned from close to 0 eV to more than 4 eV. Experimentally, we introduced the synthesis/characterization of five previously unreported PBAs (MN= Ru, Os; MC= Fe, Ru, and Os) to complete the nine stable MN:MCtransition metal combinations in group VIII of the periodic table. The optically measured intervalence charge transfer excitation energies of group VIII PBAs are consistent with calculated band gaps. They demonstrate wide band gap tunability by adjusting transition metals and oxidation states, enabling semiconductor-to-metal transitions for memristor applications and enhancing electronic conductivity for battery applications. This work provides a computational/experimental database of electronic properties versus structural compositions for PBAs.
| Original language | English |
|---|---|
| Pages (from-to) | 6140-6150 |
| Number of pages | 11 |
| Journal | Chemistry of Materials |
| Volume | 37 |
| Issue number | 16 |
| DOIs | |
| State | Published - Aug 26 2025 |
Funding
The theoretical calculations were supported by the Department of Energy (DOE) Office of Science Research Program for Microelectronics Codesign (sponsored by ASCR, BES, HEP, NP, and FES) through the Abisko Project. The synthesis and spectroscopic characterization (D.A.R. and A.A.T) were supported by the Reconfigurable Materials Inspired by Nonlinear Neuron Dynamics (REMIND) Energy Frontier Research Center, funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, awarded to Texas A&M University (award #DE-SC0023353) and at Sandia National Laboratories under contract #DE-NA-0003525. L. L. used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231 using NERSC award BES-ERCAP0031261. DFT calculations were performed at the Center for Nanophase Materials Sciences, a U.S. Department of Energy, Office of Science User Facility located at Oak Ridge National Laboratory. D. A. R. acknowledges Vitalie Stavila for x-ray diffraction training and resources. Notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains, and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan). Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC (NTESS), a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration (DOE/NNSA) under contract DE-NA0003525. This written work is authored by an employee of NTESS. The employee, not NTESS, owns the right, title, and interest in and to the written work and is responsible for its contents. Any subjective views or opinions that might be expressed in the written work do not necessarily represent the views of the U.S. Government. The publisher acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this written work or allow others to do so, for U.S. Government purposes. The DOE will provide public access to results of federally sponsored research in accordance with the DOE Public Access Plan.