NOVELTY - A solid-state p-n heterojunction comprises an n-type material in contact with a p-type material where at least one of the n-type material and the p-type material comprises an organic polymeric charge transporter having a low band gap and where the heterojunction further comprises a light harvesting antenna (LHA) material having a band gap of no less than 1.5 eV and greater than the band gap of the organic polymeric charge transporter.    USE - The solid-state p-n heterojunction is useful for preparing optoelectronic device such as solar cell, phototransistor or photo-detector, preferably a solid state dye sensitized solar cell and/or solid state polymer sensitized solar cell. The light harvesting antenna dye having a band gap of no less than 1.5 eV is useful for enhancing light absorption of at least one organic polymeric charge transporter having a low band gap (of no more than 1.9eV) where the band gap of the sensitizer is greater than the band gap of the organic polymeric charge transporter, where the sensitizer is capable of transferring excitation energy to the organic polymeric charge transporter (all claimed).    ADVANTAGE - The invention provides solid-state heterojunctions and optoelectronic devices such as solar cells comprising polymeric charge transporters that were able to absorb light over a large proportion of the visible spectrum. The solar cells could provide enhanced currents and/or enhanced efficiencies.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are:    (1) an optoelectronic device comprising at least one solid state p-n heterojunction; or an optoelectronic device such as a photovoltaic cell, phototransistor or light sensing device comprising at least one solid-state p-n heterojunction formed or formable by the method; and    (2) a method for manufacturing a solid-state p-n heterojunction comprising an organic p-type material in contact with a layer of inorganic n-type material, comprising: (a) coating an anode, preferably a transparent anode (e.g. a fluorine doped tin oxide (FTO) anode) with a compact layer of an n-type inorganic semiconductor material; (b) forming a planar or porous (preferably mesoporous) layer of an n-type semiconductor material on the compact layer; (c) optionally forming at least a partial monolayer of functionalized electron acceptor moieties and optionally sensitizing agents on the surface of the porous n-type layer; (d) optionally treating the compact layer and/or the porous layer of n-type material with at least one ionic material such as a lithium salt; (e) optionally forming a porous barrier layer of an insulating material on the porous layer of n-type material; (f) contacting the planar or porous layer of n-type material with at least one solution of at least one low band-gap polymeric organic p-type semiconductor material and at least one sensitizer (having a band gap) where to form a layer of polymeric organic p-type semiconductor having distributed at least one sensitizer; (g) optionally treating the layer produced in (f) by coating on top with a solution of ionic material, such as lithium bis(trifluoromethylsulfonyl)imide salt (Li-TFSI); (h) forming a cathode, preferably a metal cathode (e.g. a silver or gold cathode) in contact with the p-type semiconductor material.