Photoelectrochemical Hole Injection Revealed in Polyoxotitanate Nanocrystals Functionalized with Organic Adsorbates

CHRISTIAN F. A. NEGRE; KARIN J. YOUNG; MARÍA BELÉN OVIEDO; LAURA J. ALLEN; CRISTIÁN G. SÁNCHEZ; KATARZYNA N. JARZEMBSKA; JASON B. BENEDICT ; ROBERT H. CRABTREE; PHILIP COPPENS; GARY W. BRUDVIG; VICTOR S. BATISTA

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

AMER CHEMICAL SOC

Lugar: Washington; Año: 2014 vol. 136 p. 16420 - 16429

0002-7863

We find that crystallographically resolved Ti17O24(OPri)20 nanoparticles, functionalized by covalent attachment of 4-nitrophenyl-acetylacetonate or coumarin 343 adsorbates, exhibit hole injection into surface states when photoexcited with visible light (λ = 400?680 nm). Our findings are supported by photoelectrochemical measurements, EPR spectroscopy, and quantum dynamics simulations of interfacial charge transfer. The underlying mechanism is consistent with measurements of photocathodic currents generated with visible light for thin layers of functionalized polyoxotitanate nanocrystals deposited on FTO working electrodes. The reported experimental and theoretical analysis demonstrates for the first time the feasibility of p-type sensitization of TiO2 solely based on covalent binding of organic adsorbates.