We present the fabrication of TiO nanotube electrodes with high biocompatibility and extraordinary spectroscopic properties. Intense surface-enhanced resonance Raman signals of the heme unit of the redox enzyme Cytochrome b were observed upon covalent immobilization of the protein matrix on the TiO surface, revealing overall preserved structural integrity and redox behavior. The enhancement factor could be rationally controlled by varying the electrode annealing temperature, reaching a record maximum value of over 70 at 475 °C. For the first time, such high values are reported for non-directly surface-interacting probes, for which the involvement of charge-transfer processes in signal amplification can be excluded. The origin of the surface enhancement is exclusively attributed to enhanced localized electric fields resulting from the specific optical properties of the nanotubular geometry of the electrode.

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Conjugated polymers featuring tunable band gaps/ positions and tailored active centers,a re attractive photoelectrode materials for water splitting.However,their exploration falls far behind their inorganic counterparts.H erein, we demonstrate amolecular engineering strategy for the tailoring aromatic units of conjugated acetylenic polymers from benzene-to thiophene-based. The polarized thiophene-based monomers of conjugated acetylenic polymers can largely extend the light absorption and promote charge separation/ transport. The C Cb onds are activated for catalyzing water reduction. Using on-surface Glaser polycondensation, asfabricated poly(2,5-diethynylthieno[3,2-b]thiophene) on commercial Cu foam exhibits ar ecordH 2 -evolution photocurrent density of 370 mAcm À2 at 0.3 Vv s. reversible hydrogen electrode among current cocatalyst-free organic photocathodes (1-100 mAcm À2 ). This approach to modulate the optical, charge transfer,a nd catalytic properties of conjugated polymers paves ac ritical way towardh igh-activity organic photoelectrodes.

Wirp r äsentieren die Herstellung von TiO 2 -Nanorçhren-Elektroden mit hoher Biokompatibilitätu nd außergewçhnlichen spektroskopischen Eigenschaften. Intensive oberflächenverstärkte Resonanz-Raman-Signale der Häm-Gruppe des kovalent an die Elektrodenoberflächei mmobilisierten Redox-Enzyms Cytochrom b 5 wurden beobachtet, die auf konservierte Proteinstruktur und Redox-Eigenschaften schließen lassen. Der Verstärkungsfaktor konnte selektiv über die Kalzinierungstemperatur kontrolliert werden, wobei ein Rekordwert von über 70 bei einer Temperatur von 475 8 8Cg efunden wurde.Z um ersten Mal konnten damit solche hohen Werte füre ine nicht direkt oberflächengebundene Probe erreicht werden, bei der chemische Verstärkungseffekte ausgeschlossen werden kçnnen. Damit sind die hohen Verstärkungsfaktoren ausschließlichauf lokalisierte elektrische Felder zurückzuführen, hervorgerufen durch die spezifischen opti-schenE igenschaften der nanotubularen Geometrie der Elektroden. [*] M. Sc. I. H. Öner,P rof. Dr.I .M.W eidinger Professur

We present a facile approach for the determination of the electromagnetic field enhancement of nanostructured TiN electrodes. As model system, TiN with partially collapsed nanotube structure obtained from nitridation of TiO2 nanotube arrays was used. Using surface-enhanced Raman scattering (SERS) spectroscopy, the electromagnetic field enhancement factors (EFs) of the substrate across the optical region were determined. The non-surface binding SERS reporter group azidobenzene was chosen, for which contributions from the chemical enhancement effect can be minimized. Derived EFs correlated with the electronic absorption profile and reached 3.9 at 786 nm excitation. Near-field enhancement and far-field absorption simulated with rigorous coupled wave analysis showed good agreement with the experimental observations. The major optical activity of TiN was concluded to originate from collective localized plasmonic modes at ca. 700 nm arising from the specific nanostructure.