RT info:eu-repo/semantics/article T1 In-situ evidence of the redox-state dependence of photoluminescence in graphene quantum dots A1 Barrera, Joaquín A1 Ibáñez Martínez, David A1 Heras Vidaurre, Aránzazu A1 Ruiz Fernández, Virginia A1 Colina Santamaría, Álvaro K1 Química analítica K1 Chemistry, Analytic AB 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. PB American Chemical Society SN 1948-7185 YR 2017 FD 2017-01 LK http://hdl.handle.net/10259/4948 UL http://hdl.handle.net/10259/4948 LA eng NO Ministerio de Economía y Competitividad(CTQ2014-55583-R, CTQ2014-61914-EXP, CTQ2015-71955-REDT), Junta de Castilla y León (BU033-U16) andBasque Government under the ELKARTEK Program (ACTIMATproject, grant number KK-2015/00094 and KK-2016/00097) DS Repositorio Institucional de la Universidad de Burgos RD 29-mar-2024