Composite structures of p-type mesoporous silicon and polyaniline have been fabricated by a one-step electrochemical polymerization process. The composite structure shows good conduction properties and new, intense photoluminescence emission bands that are assigned to polyaniline that penetrates and fulfills the entire volume of the porous silicon matrix quite uniformly. We have found that at room temperature, the reverse bias conductivity of the composite structure is related to transport through the polyaniline network, giving rise to a 5 orders of magnitude larger current relative to that of a reference porous silicon matrix. At low temperatures, the current at both polarities of the bias voltage is carried in the polyaniline network and is related to variable range hopping in three dimensions.

Time decay of fluorescence of tris(8-hydroxyquinoline) aluminum (Alq₃) and tris(ruthenium bipyridyl chloride) (Rubpy) in silica, zirconia, tin oxide and ormocer films prepared by the sol–gel method were studied by laser induced fluorescence. The lifetimes of Rubpy are unchanged in the presence of Alq₃ while the lifetimes of the Alq₃are decreased in the co-doped species as a result of electron transfer or non-radiative energy transfer between Alq₃ and Rubpy. The energy transfer is reflected also by overlap between absorption of Rubpy and emission of Alq₃.

The formation of gold crystallites on the surface of S8 promotes diffusion of electrons and determines the conductive properties of the shell-core nanosystems. Conducting probe atomic microscopy and four-probe resistance measurements confirmed that Au/S8 shell-core systems exhibit electrical conductivity on the micro- as well as on the nanoscale in contrast to non-covered S8 crystals, which are insulating. The conductivity of Au/S8systems on the microscale was measured to be 10 ± 1 S · cm-1. In XPS measurements, a single peak at 163.6 eV was observed for bulk S8 whereas an additional peak corresponding to a binding energy of 161.4 eV appeared for S8 adsorbed on a Au substrate. This is interpreted to mean that a chemical reaction has taken place. A process which results in adsorption of uniform gold nanolayers on needle shaped or fibrous S8 crystallites is under investigation.

Composite structures of p-type meso-porous silicon (PS) and polyaniline (PAN) have been fabricated by electrochemical polymerization process. The composite structure provides a unique way to control the conduction either through the porous silicon matrix or via the polyaniline, by changing the polarity of the applied bias voltage. In addition, photoluminescence (PL) experiments revealed enhanced PL emission at the green wavelengths that are originated from the polyaniline network, rather than the porous silicon. The above composite structure can be used as a building block for improved electroluminescence and light emitting devices in a wide range of applications.