Formation and Photoinduced Electron Transfer in Porphyrin- and Phthalocyanine-Bearing N-Doped Graphene Hybrids Synthesized by Click Chemistry |
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Authors: | Dr Luis M Arellano Dr Habtom B Gobeze Youngwoo Jang Dr Myriam Barrejón Dr Concepción Parejo Dr Julio C Álvarez Dr María J Gómez-Escalonilla Prof Ángela Sastre-Santos Prof Francis D'Souza Prof Fernando Langa |
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Institution: | 1. Universidad de Castilla-La Mancha, Instituto de Nanociencia, Nanotecnología y Materiales Moleculares (INAMOL), Avda. Carlos III, s/n, 45071- Toledo, Spain;2. Department of Chemistry and Materials Science and Engineering, University of North Texas, Denton, TX 76203-5017 USA;3. Neural Repair and Biomaterials Laboratory, Hospital Nacional de Parapléjicos (SESCAM), Finca la Peraleda s/n, 45071 Toledo, Spain;4. Área de Química Orgánica, Instituto de Bioingeniería, Universidad Miguel Hernández, Avda. de la Universidad, s/n, Elche, 03202 Spain |
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Abstract: | Graphene doped with heteroatoms such as nitrogen, boron, and phosphorous by replacing some of the skeletal carbon atoms is emerging as an important class of two-dimensional materials as it offers the much-needed bandgap for optoelectronic applications and provides better access for chemical functionalization at the heteroatom sites. Covalent grafting of photosensitizers onto such doped graphenes makes them extremely useful for light-induced applications. Herein, we report the covalent functionalization of N-doped graphene (NG) with two well-known electron donor photosensitizers, namely, zinc porphyrin (ZnP) and zinc phthalocyanine (ZnPc), using the simple click chemistry approach. Covalent attachment of ZnP and ZnPc at the N-sites of NG in NG−ZnP and NG−ZnPc hybrids was confirmed by using a range of spectroscopic, thermogravimetric and imaging techniques. Ground- and excited-state interactions in NG−ZnP and NG−ZnPc were monitored by using spectral and electrochemical techniques. Efficient quenching of photosensitizer fluorescence in these hybrids was observed, and the relatively easier oxidations of ZnP and ZnPc supported excited-state charge-separation events. Photoinduced charge separation in NG−ZnP and NG−ZnPc hybrids was confirmed by using the ultrafast pump-probe technique. The measured rate constants were of the order of 1010 s,−1 thus indicating ultrafast electron transfer phenomena. |
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Keywords: | Keywords: click chemistry N-doped graphene photoinduced electron-transfer zinc phthalocyanines zinc porphyrins |
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