TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The at least one ionic species is Li+, Na+, K+, Cs+, Mg+, Ca+2, triflimide, halide, perchlorate, trihalate or their BARF salts. The conducting material comprises an ohmic conductor and is metal, graphite, a highly-doped semiconductor or an organic conductor. The conducting material comprises a semiconducting material and is TiO2, NO, SnO, Ta2O5, Nb2O5, WO3, OMeTAD, PPV, CU-phthalocyanine, polythiophene, polypyrrole, pentacene or perylene. The conducting material comprises an ionic conductor and is a polymer electrolyte or polymer supporting a redox active species. The semiconductor is TiO2, ZnO, SnO, Ta2O5, Nb2O5, WO3, OMETAD, poly(para-phenylenevinylene) (PPV), Cu-phthalocyanine, oligo- or polythiophene, polypyrroles, TPDs, pentacene or perylene. The semiconductor is porous and the dual-function material is at least partially contained within the pores of the semiconductor. Preferred Definitions:    (Y) = a moiety of formula Ar3-N(Ar1)-Ar2, poly(1,4-phenylene), polypyrrole, poly(para-phenylenevinylene) (PPV), poly(thiophene), MEH-PPV, polyaniline or PEDOT;    Ar1-Ar2 = optionally substituted (hetero)aromatic rings or fused or their conjugated derivatives;    X = -((CH2CH2O)nCH2CH2OCH3), (-(OCH2CH2)nOCH3), (-CH2CH(R)O)nCH2CH2OCH3) or (-(OCH(R)CH2)nOCH3;    n = 2 - 10 (preferably 2 - 4);    R = straight or branched 1-10C (preferably 1-2C) alkyl, crown ether, podant, lariat ether, cryptand or spherand.    EXAMPLE - A dye sensitized nanocrystalline TiO2 film was prepared on a glass substrate. The glass substrate was provided with a conducting coating of fluorine-doped tin oxide. A TiO2 paste, consisting of l5 nm sized particles was prepared from a sol-gel colloidal suspension containing TiO2 particles (12.5 wt.%) and Carbowax 20000 (TM) (A) (6.2 wt.%). The titania particles were produced by injecting titanium iso-propoxide (20 ml) into glacial acetic acid (5.5 g) under an atmosphere of argon followed by stirring for 10 minutes. The mixture was then injected into 0.1 M nitric acid (120 ml) under an anhydrous atmosphere at room temperature and stirred vigorously. The resultant solution was left uncovered and heated at 80 degrees C for 8 hours. After cooling, the solution was filtered, diluted to 5 wt.% TiO2 by the addition of water and then heated at 220 degrees C for 12 hours. The resultant colloid was re-dispersed with a 60 second cycle burst and then concentrated to 12.5 %. (A) was added and the resulting paste was stirred slowly overnight to ensure homogeneity. The paste was spread onto the glass substrate with a glass rod. The film was dried and then sintered at 450 degrees C for 20 minutes. The thickness of the TiO2 film was 3 mu. The TiO2 film was sensitized by immersing it in a 1 mM solution of a RuL2(NCS)2 dye in 1:1 acetonitrile/tert-butanol. Rinsing in ethanol removed any unadsorbed dye. A layer of a dual function material was then deposited as follows: a solution was prepared by dissolving polymer A of formula (I) and lithium triflimide, at a mole ratio of 1:12, in a chlorobenzene/acetonitrile solvent mixture (1:9 volume ratio). The dye sensitized TiO2 film was immersed in the polymer A solution for 2 hours at a temperature of 70 degrees C, which resulted in the conformal deposition of a layer of the dual function material on the surface of the dye sensitized, nanocrystalline TiO2 film. A hole-transporting semiconducting layer of a spiro-OMeTAD material was then deposited onto the layer of dual-function material by spin coating from solvent solution (0.2 M solution in chlorobenzene for 60 seconds). This solution did not contain any added ionic species, chemical dopants or ion-solvating species. The resulting sample was left under vacuum for 2 hours and then transferred to a thermal evaporator. A gold contact was deposited under a pressure of 1 - 2x106 atmosphere. This provided a photo-voltaic cell incorporating the composite structure. For comparative purposes, a second device was prepared omitting the layer of dual-function material. Both devices prepared had a cell area of 0.2 cm2 and were exposed to 10 mWcm-2 of simulated AM1.5 solar irradiation during data collection. The current-voltage characteristics of the device showed an efficient photovoltaic response. By contrast, the device absent the layer of dual function material showed a negligible photovoltaic response.