Electronic Conductivity in a Porous Vanadyl Prussian Blue Analogue upon Air Exposure

• Published in: Inorganic chemistry Vol. 56; no. 21; pp. 12682 - 12686
• Main Authors: Manumpil, Mary Anne, Leal-Cervantes, Carmen, Hudson, Matthew R, Brown, Craig M, Karunadasa, Hemamala I
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 06.11.2017
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.7b02051

Exposure to humid O2 or ambient air affords a 5-order-of-magnitude increase in electronic conductivity of a new Prussian blue analogue incorporating CoII and VIV-oxo units. Oxidation produces a mixed-valence framework, where the O2 exposure time controls the VIV/VV ratio and thereby the material’s conductivity. The oxidized framework shows an intervalence charge-transfer band at ca. 4200 cm–1, consistent with mixed valence. The mixed-valence frameworks show semiconducting behavior with conductivity values of 10–5 S·cm–1 at room temperature and 10–4 S·cm–1 at 100 °C and activation energies of ca. 0.3 eV. N2 adsorption measurements at 77 K show that these materials possess permanent porosity before and after oxidation with Brunauer–Emmett–Teller surface areas of 340 and 370 m2·g–1, respectively.