TY - JOUR
T1 - Conductivity in Open-Framework Chalcogenides Tuned via Band Engineering and Redox Chemistry
AU - McKenzie, Jacob
AU - Le, Khoa N.
AU - Bardgett, Dylan J.
AU - Collins, Kelsey A.
AU - Ericson, Thomas
AU - Wojnar, Michael K.
AU - Chouinard, Julie
AU - Golledge, Stephen
AU - Cozzolino, Anthony F.
AU - Johnson, David C.
AU - Hendon, Christopher H.
AU - Brozek, Carl K.
N1 - Funding Information:
This material was based upon work supported by the National Science Foundation through the Division of Materials Research under grant no. DMR-1956403 and through the Department of Energy through the Office of Basic Energy Sciences under grant no. DE-SC0022147. C.H.H. acknowledges the Research Corporation for Science Advances (Cottrell Award). The authors also acknowledge the continued support from the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by the National Science Foundation (ACI-1548562). The authors thank Dr. D. Freedman for assistance with magnetic measurement collection and analysis.
Publisher Copyright:
© 2022 American Chemical Society
PY - 2022/2/22
Y1 - 2022/2/22
N2 - “Open-framework chalcogenides” are an important class of materials that combine porosity with semiconductor behavior, and yet fundamental aspects of their conductivity remain unexplored. Here, we report a combined experimental-computational approach to the iconic subclass of materials TMA2MGe4Q10 (TMA = tetramethyl ammonium; M = Mn, Fe, Co, Ni, Zn; Q = S, Se). Direct current (DC) conductivity measurements and density functional theory (DFT) modeling reveal that metal ion and chalcogenide identities dominate key properties of the band structures, while impedance spectroscopy reveals purely electronic band-type transport in the Fe frameworks and redox-type mixed ion-electron conductivity in the others. Redox chemistry and computation suggest that the unique conductivity of Fe arises from its propensity toward Fe2+/Fe3+ mixed valency as a source of p-type doping and from its highly covalent bonds that ensure high carrier mobilities. Taken together, these results demonstrate open-framework chalcogenides as a well-defined platform for understanding porous semiconductors and for achieving highly tunable electronic performance.
AB - “Open-framework chalcogenides” are an important class of materials that combine porosity with semiconductor behavior, and yet fundamental aspects of their conductivity remain unexplored. Here, we report a combined experimental-computational approach to the iconic subclass of materials TMA2MGe4Q10 (TMA = tetramethyl ammonium; M = Mn, Fe, Co, Ni, Zn; Q = S, Se). Direct current (DC) conductivity measurements and density functional theory (DFT) modeling reveal that metal ion and chalcogenide identities dominate key properties of the band structures, while impedance spectroscopy reveals purely electronic band-type transport in the Fe frameworks and redox-type mixed ion-electron conductivity in the others. Redox chemistry and computation suggest that the unique conductivity of Fe arises from its propensity toward Fe2+/Fe3+ mixed valency as a source of p-type doping and from its highly covalent bonds that ensure high carrier mobilities. Taken together, these results demonstrate open-framework chalcogenides as a well-defined platform for understanding porous semiconductors and for achieving highly tunable electronic performance.
UR - http://www.scopus.com/inward/record.url?scp=85124526174&partnerID=8YFLogxK
U2 - 10.1021/acs.chemmater.1c04285
DO - 10.1021/acs.chemmater.1c04285
M3 - Article
AN - SCOPUS:85124526174
SN - 0897-4756
VL - 34
SP - 1905
EP - 1920
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 4
ER -