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Tuning the CrIV/CrIII valence states in purple Cr-doped SnO2 nanopowders : the key role of CrIV centers and defects

dc.rights.licenseopen
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorSERMENT, Béatrice
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorGAUDON, Manuel
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorTOULEMONDE, Olivier
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorDUTTINE, Mathieu
hal.structure.identifierLaboratoire de Chimie des Polymères Organiques [LCPO]
dc.contributor.authorBROCHON, Cyril
hal.structure.identifierInstitut de Chimie de la Matière Condensée de Bordeaux [ICMCB]
dc.contributor.authorDEMOURGUES, Alain
dc.date.accessioned2020
dc.date.available2020
dc.date.issued2019
dc.identifier.issn0020-1669
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/19652
dc.description.abstractEnA low content of chromium (≤5 mol %) has been incorporated into a SnO2 cassiterite by a coprecipitation route in a basic medium, followed by an annealing step under an O2 flow at T = 800 °C and T = 1000 °C. Accurate UV–vis and EPR spectroscopy investigations show the coexistence of isolated Cr4+ and Cr3+ ions as well as ferromagnetic Cr4+–Cr3+ and antiferromagnetic Cr3+–Cr3+ interactions. The strong purple hue is related to the isolated Cr4+ ions stabilized in a distorted octahedral site. This is thanks to the second-order Jahn–Teller (SOJT) effect with a crystal field splitting 10Dq value around 2.4 eV, whereas the 10Dq value is around 2 eV for isotropic Cr3+ ions, partially substituted for Sn4+ ions in cassiterite. Just after the coprecipitation process, only Cr3+ species are stabilized in this rutile network with a poor crystallinity. The isolated Cr4+ content remains high after annealing at 800 °C for 2 days especially for the highest Cr rate (2 and 5 mol %), leading to a darker purple color, but unfortunately the Cr3+ content also increases for a higher Cr concentration. A lighter purple hue can be reached after calcination at a higher temperature (T = 1000 °C) for a shorter time (4 h) but with a lower Cr content to avoid Cr clusters. This is due to stabilizing a high content of isolated Cr4+ species and limiting the Cr4+–Cr3+ ferromagnetic interactions, which are optimal for a 2% Cr content and also cause the color to darken. The key roles of the Cr4+ rate and the Cr4+–Cr3+ clusters create local defects whose concentration strongly varies with a total Cr content, which have then been demonstrated to strongly influence the optical and magnetic properties.
dc.language.isoen
dc.publisherAmerican Chemical Society
dc.title.enTuning the CrIV/CrIII valence states in purple Cr-doped SnO2 nanopowders : the key role of CrIV centers and defects
dc.typeArticle de revue
dc.identifier.doi10.1021/acs.inorgchem.9b02943
dc.subject.halChimie/Matériaux
bordeaux.journalInorganic Chemistry
bordeaux.page678-686
bordeaux.volume59
bordeaux.hal.laboratoriesLaboratoire de Chimie des Polymères Organiques (LCPO) - UMR 5629*
bordeaux.issue1
bordeaux.institutionBordeaux INP
bordeaux.institutionUniversité de Bordeaux
bordeaux.peerReviewedoui
hal.identifierhal-02490016
hal.version1
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-02490016v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Inorganic%20Chemistry&rft.date=2019&rft.volume=59&rft.issue=1&rft.spage=678-686&rft.epage=678-686&rft.eissn=0020-1669&rft.issn=0020-1669&rft.au=SERMENT,%20B%C3%A9atrice&GAUDON,%20Manuel&TOULEMONDE,%20Olivier&DUTTINE,%20Mathieu&BROCHON,%20Cyril&rft.genre=article


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