Enhancing Light Absorption and Charge Transfer Efficiency in Carbon Dots through Graphitization and Core Nitrogen Doping

Benjamin C M Martindale; Georgina A M Hutton; Christine A Caputo; Sebastian Prantl; Robert Godin; James R Durrant; Erwin Reisner

doi:10.1002/anie.201700949

Enhancing Light Absorption and Charge Transfer Efficiency in Carbon Dots through Graphitization and Core Nitrogen Doping

Angew Chem Int Ed Engl. 2017 Jun 1;56(23):6459-6463. doi: 10.1002/anie.201700949. Epub 2017 May 2.

Authors

Benjamin C M Martindale¹, Georgina A M Hutton¹, Christine A Caputo^{1

2}, Sebastian Prantl³, Robert Godin³, James R Durrant³, Erwin Reisner¹

Affiliations

¹ Christian Doppler Laboratory for Sustainable SynGas Chemistry, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, UK.
² Current address: Department of Chemistry, University of New Hampshire, 23 Academic Way, Durham, NH, 03824, USA.
³ Department of Chemistry, Imperial College London, Exhibition Road, London, SW7 2AZ, UK.

PMID: 28464489
DOI: 10.1002/anie.201700949

Abstract

Single-source precursor syntheses have been devised for the preparation of structurally similar graphitic carbon dots (CDs), with (g-N-CD) and without (g-CD) core nitrogen doping for artificial photosynthesis. An order of magnitude improvement has been realized in the rate of solar (AM1.5G) H₂ evolution using g-N-CD (7950 μmol_H2 (g_CD )^-1 h^-1 ) compared to undoped CDs. All graphitized CDs show significantly enhanced light absorption compared to amorphous CDs (a-CD) yet undoped g-CD display limited photosensitizer ability due to low extraction of photogenerated charges. Transient absorption spectroscopy showed that nitrogen doping in g-N-CD increases the efficiency of hole scavenging by the electron donor and thereby significantly extends the lifetime of the photogenerated electrons. Thus, nitrogen doping allows the high absorption coefficient of graphitic CDs to be translated into high charge extraction for efficient photocatalysis.

Keywords: carbon dots; doping; excited state dynamics; light harvesting; photocatalysis.

Publication types

Research Support, Non-U.S. Gov't