Influence of crystallinity and energetics on charge separation in polymer-inorganic nanocomposite films for solar cells.

The dissociation of photogenerated excitons and the subsequent spatial separation of the charges are of crucial importance to the design of efficient donor-acceptor heterojunction solar cells. While huge progress has been made in understanding charge generation at all-organic junctions, the process in hybrid organic:inorganic systems has barely been addressed. Here, we explore the influence of energetic driving force and local crystallinity on the efficiency of charge pair generation at hybrid organic:inorganic semiconductor heterojunctions.

Thermal decomposition of solution processable metal xanthates on mesoporous titanium dioxide films: a new route to quantum-dot sensitised heterojunctions.

We introduce a straightforward route to the fabrication of metal sulfide semiconductor (e.g. CdS, Sb(2)S(3), Bi(2)S(3)) sensitised TiO(2) films.

Toward Antimony Selenide Sensitized Solar Cells: Efficient Charge Photogeneration at spiro-OMeTAD/Sb2Se3/Metal Oxide Heterojunctions.

Photovoltaic devices comprising metal chalcogenide nanocrystals as light-harvesting components are emerging as a promising power-generation technology. Here, we report a strategy to evenly deposit Sb2Se3 nanoparticles on mesoporous TiO2 as confirmed by Raman spectroscopy, energy-dispersive X-ray spectrometry, and transmission electron microscopy. Detailed study of the interfacial charge transfer dynamics by means of transient absorption spectroscopy provides evidence of electron injection across the Sb2Se3/TiO2 interface upon illumination, which can be improved 3-fold by annealing at low temperatures.

Charge photogeneration in hybrid solar cells: a comparison between quantum dots and in situ grown CdS.

We demonstrate that blend films containing poly(3-hexylthiophene-2,5-diyl) and in situ grown CdS display a greater yield of photogenerated charges than a blend containing an equivalent amount of pre-synthesised CdS quantum dots. Moreover, we show that the greater charge yield in the in situ grown films leads to an improvement in device efficiency. The present findings also appear to suggest that charge photogeneration at the CdS/polymer heterojunction is facilitated by the formation of nanoparticle networks as a result of CdS aggregation.

Interfacial electron transfer on cytochrome-c sensitised conformally coated mesoporous TiO2 films.

Hybrid protein films incorporating Cyt-c immobilized on TiO(2) films were prepared and characterised optically with UV-visible spectroscopy and electrochemically with cyclic voltammetry, and their conductivity properties were studied in detail. In addition the effects of a thin overlayer coating of a second metal oxide such as SiO(2), Al(2)O(3), ZrO(2) and MgO(2) were studied and the effects over the electrochemical properties of the hybrid working electrodes were discussed.

Control of charge recombination dynamics in dye sensitized solar cells by the use of conformally deposited metal oxide blocking layers.

We report herein a methodology for conformally coating nanocrystalline TiO2 films with a thin overlayer of a second metal oxide. SiO2, Al2O3, and ZrO2 overlayers were fabricated by dipping mesoporous, nanocrystalline TiO2 films in organic solutions of their respective alkoxides, followed by sintering at 435 degrees C. These three metal oxide overlayers are shown in all cases to act as barrier layers for interfacial electron transfer processes.

Slow charge recombination in dye-sensitised solar cells (DSSC) using Al2O3 coated nanoporous TiO2 films.

The conformal growth of an overlayer of Al2O3 on a nanocrystalline TiO2 film is shown to result in a 4-fold retardation of interfacial charge recombination, and a 30% improvement in photovoltaic device efficiency.