The fabrication of surface-enhanced Raman spectroscopy (SERS) substrates that are optimized for use with specifi c laser wavelength-analyte combinations is addressed. In order to achieve large signal enhancement, temporal stability, and reproducibility over large substrate areas at low cost, only self-assembly and templating processes are employed. The resulting substrates consist of arrays of gold nanospheres with controlled diameter and spacing, properties that dictate the optical response of the structure. Tunability of the extended surface plasmon resonance is observed in the range of 520-1000 nm. It is demonstrated that the enhancement factor is maximized when the surface plasmon resonance is red-shifted with respect to the SERS instrument laser line. Despite relying on self-organization, site-to-site enhancement factor variations smaller than 10% are obtained.

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In the present study, a thin layer of Cu-based metal–organic frameworks (MOFs, copper(II) benzene-1,3,5-tricarboxylate) is fabricated using a layer-by-layer technique, and the layer is investigated as a light-absorbing layer in TiO2-based solar cells. Iodine doping of the MOFs is performed to improve the conductivity and charge-transfer reaction across the TiO2/MOF/electrolyte interface. The HOMO and LUMO energy states of the MOF films are estimated to be −5.37 and −3.82 eV (vs vacuum), respectively, which show a well-matched energy cascade with TiO2. For the first time, a TiO2-based solar cell is fabricated successfully using iodine-doped Cu-MOFs as an active layer, demonstrating a cell performance with J sc = 1.25 mA cm–2 and Eff = 0.26% under illumination of 1 sun radiation. In contrast, the cell with an undoped MOF layer exhibited J sc = 0.05 mA cm–2 and Eff = 0.008%. Electrochemical impedance spectroscopy of the cells suggests that iodine doping significantly reduces the charge-transfer resistance.

A 50% enhancement in the conversion efficiency (4.9-7.37%) is realized in dye-sensitized solar cells using hydrothermally synthesized TiO(2)-multiwalled carbon nanotube (MWCNT) nanocomposites as compared to hydrothermally synthesized TiO(2) without MWCNT and Degussa P25. Several characterizations have been employed to reveal the nature of the modification imparted to the MWCNTs under hydrothermal processing conditions and the resulting TiO(2)-MWCNT conjugation through -COOH groups. Efficient charge transfer in the nanocomposite and efficient electron transport by MWCNT (significantly higher incident-photon-to-current conversion efficiency) are suggested to be the possible reasons for the enhancement.