TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Materials: The nanoparticles (III) comprise an inorganic core (IIIa) consisting of metal(s) and/or metal-containing semiconductive compounds, to which at least one organic ligand (IIIb) containing the group Y is bonded. Specifically (IIIa) is cadmium selenide, cadmium telluride, zinc oxide, lead selenide, lead sulfide, indium phosphide, copper-indium sulfide (CuInS2), copper-indium selenide (CuInSe2), copper-(indium/gallium) selenide (Cu(In,Ga)Se2), gallium arsenide, indium gallium arsenide, silicon, germanium, gold, silver or platinum; and (IIIb) is of formula BG-(SG)p-Y (III'b).BG = linker group for bonding to the microparticles, specifically thiol dithiol, carbodithioate, dithiocarbamate, xanthate, carboxylic acid, dicarboxylic acid, phosphonic acid, diphosphonic acid, sulfonic acid or hydroxamic acid;SG = spacer group, specifically an aliphatic spacer;p = 0 or 1.The support (A) is of glass, mica, silicon (including an oxide layer) or indium-tin oxide.    TECHNOLOGY FOCUS - POLYMERS - Preferred Process: Steps (a) and (b) are repeated alternately. The groups X and Y contain carbon chain structures of formulae -CH(Jx)-Kx-CH(Lx)- and -CH(Jy)-Ky-CH(Ly)-, where hydrogen bonds are formed between at least two of the pairs Jx/Jy, Kx/Ky and Lx/Ly.One of Jx, Jy = N or O covalently bonded to H; and the other = N or O having a pi -type bond;one of Kx, Ky = N covalently bonded to H; and the other = N having a pi -type bond; Lx, Ly independently = H, C, N or O covalently bonded to H or N or O having a pi -type bond.In particular the X/Y pairs are diamino-pyrimidine/thymine, diamino-triazine/uracil, diamino-triazine/maleimide, diacylamino-triazine/uracil, diamino-triazine/perylene-bis-imide, urea/imide units or ureido-s-triazine or ureidopyrimidinone dimer. (II) are especially selected from copolymers of poly(anilines), poly(alkylthiophenes), poly(p-phenylenes), poly(p-phenylene-vinylenes), poly(fluorenes), poly(pyrroles), poly(acetylenes), polyaromatic amines, poly(thienylene-vinylenes) or their derivatives, which include modified monomer units containing the group X (preferably at 5-50%). In particular (II) is poly(3-hexylthiophene) functionalized with diaminopyrimidine. Deposition is carried out by immersing the support (A) in polymer solutions containing the groups X and Y. EXAMPLE - Poly-(3-hexylthiothene-co-3-(6-bromohexyl)-thiophene) (number average molecular weight 12800) was post-functionalized with diaminopyrimidine (DAP) groups (hexylthiophene to DAP unit ratio 9:1) by reaction with 2,4-diamino-6-hydroxypyrimidine in a basic medium, to give a conjugated organic polymer (IIA). Cadmium selenide (CdSe) nanoparticles (average diameter 6.1; coated during synthesis with stearic acid) were reacted with 1-(6-mercaptohexyl)-thymine (MHT) in chloroform to give nanocrystals (IIIA) having 70% of the surface coated with MHT ligands. A 1.1 mm thick glass plate, precoated on one face with a cleaned layer of indium-tin oxide (surface resistivity 8-12 Ohm/cm2), was immersed in 1 g/l solution of (IIA) in chloroform for 2 minutes, rinsed with chloroform, dried, immersed in 0.2 g/l dispersion of (IIIA) in dimethyl formamide: methanol (10/1) for 5 minutes and dried. The alternate coating procedure was repeated until 25 layers of each type of coating were obtained. A coated substrate of this type was used (together with lithium fluoride and aluminum layers and chromium-gold contacts) to produce a photovoltaic device of the solar cell type, having a conversion yield of 0.015%.