2026-07-24T18:48:07Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/49482022-12-20T11:50:11Zcom_10259_3844com_10259_5086com_10259_2604col_10259_3845

Barrera, Joaquín Ibáñez Martínez, David Heras Vidaurre, Aránzazu Ruiz Fernández, Virginia Colina Santamaría, Álvaro 2018-09-12T11:41:39Z 2018-09-12T11:41:39Z 2017-01 1948-7185 http://hdl.handle.net/10259/4948 10.1021/acs.jpclett.6b02694 Changes in the optical properties of graphene quantum dots (GQD) during electrochemical reduction and oxidation were investigated by photoluminescence (PL) spectroelectrochemistry, which provided direct in situ evidence of the dependence of GQD luminescence on their redox state. We demonstrated that GQD PL intensity was enhanced upon reduction (quantum yield increased from 0.44 to 0.55) and substantially bleached during oxidation (quantum yield ∼0.12). Moreover, PL emission blue/red-shifted upon GQD reduction/oxidation, rendering information about electronic transitions involved in the redox processes, namely, the π → π* and the n → π* transitions between energy levels of the aromatic sp2 domains and the functional groups, respectively. PL intensity changes during GQD reduction/oxidation resulted from a variation in structural changes in GQD as a result of charge injection, as corroborated by in situ Raman spectroelectrochemistry. Ministerio de Economía y Competitividad (CTQ2014-55583-R, CTQ2014-61914-EXP, CTQ2015- 71955-REDT), Junta de Castilla y León (BU033-U16) and Basque Government under the ELKARTEK Program (ACTIMAT project, grant number KK-2015/00094 and KK-2016/ 00097) application/pdf eng American Chemical Society The Journal of Physical Chemistry Letters. 2017, V. 8, n. 2, p. 531–537 https://doi.org/10.1021/acs.jpclett.6b02694 info:eu-repo/grantAgreement/MINECO/CTQ2014-55583-R info:eu-repo/grantAgreement/MINECO/CTQ2014-61914-EXP info:eu-repo/grantAgreement/MINECO/CTQ2015-71955-REDT info:eu-repo/grantAgreement/JCyL/BU033-U16 info:eu-repo/grantAgreement/GV/KK-2015-00094 info:eu-repo/grantAgreement/GV/KK-2016-00097 Química analítica Chemistry, Analytic In-situ evidence of the redox-state dependence of photoluminescence in graphene quantum dots info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion info:eu-repo/semantics/openAccess