We review progress in the development of organic–inorganic hybrid photovoltaic materials consisting of a conjugated polymer as an electron donor and a nanocrystalline metal oxide as the electron acceptor. We distinguish two main approaches: (1) where a rigid porous metal oxide structure is filled with polymer and (2) where metal oxide nanoparticles and polymer are co-deposited from solution to form a blend film. In the case of porous structures, performance is limited by the infiltration of polymer into the pores of the metal oxide and control of the nanostructure dimensions. In the case of blends, control of the blend morphology and transport between nanoparticles are limitations. In both cases, further improvements are possible by modifying the metal oxide organic interface to optimise charge transfer, by improving both inter- and intra-particle transport within the metal oxide phase, for example by the use of single crystalline nanorods, and by optimising the choice of electrode materials. Though unlikely to achieve the highest photocurrents, the polymer–metal oxide composites provide a model system to study the effects of interface properties and film morphology on the performance of bulk heterojunction photovoltaic devices.

Visible photoluminescence (PL) broad bands are observed in the Raman spectra of SiC nanoparticles (np-SiC) with diameters ranging from 10 to 25 nm. The phenomenon is studied versus the particle size, chemical composition, annealing, and oxidation treatments. In the case of quasistoichiometric np-SiC, excitation by 514-nm radiation gives rise to broad red PL emissions mainly enhanced by the amorphous fraction of the particles and by the surface chemical disorder induced by oxidation. The PL spectra are quantitatively analyzed using numerical methods based on cluster approaches. PL bands are calculated as a function of the cluster geometry and defects (carbon and silicon vacancies), as well as the oxygen location within np-SiC sites. The relevance of this numerical analysis is discussed to account for the main features of the PL broad structure. The PL signature in SiC nanopowders can be used to monitor the physical organization of the np-SiC and to point out their amorphous structure fraction, surface states, and the defect contents.