An electrically conductive composite material comprising: an electrically conductive polymer, and at least one metal nanoparticle coated with a protective agent, wherein said protective agent comprises a compound comprising a first part that has at least part of a molecular backbone of said electrically conductive polymer and a second part that interacts with said at least one metal nanoparticle, wherein said electrically conductive polymer is selected from polyaniline, polythiophene, polypyrrole, polyphenylenevinylene, polythienylenevinylene, and derivatives thereof, wherein, when said electrically conductive polymer comprises polyaniline, said protective agent is selected from 4-aminothiophenol, 2-aminothiophenol, 3-aminothiophenol, 2-aminobenzenesulfonic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 2-aminobenzonitrile, 3-aminobenzonitrile, 4-aminobenzonitrile, 2-aminobenzyl cyanide, 3-aminobenzyl cyanide, 4-aminobenzyl cyanide, N-phenyl-1,2-phenylenediamine, N-phenyl-1,4-phenylenediamine, or a copolymer of N-vinylpyrrolidone and N-phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine, wherein, when said electrically conductive polymer comprises polythiophene or polythienylenevinylene, said protective agent is selected from 3-(2-thienyl)-DL-alanine, 4-(2-thienyl)butyric acid, 2-(2-thienyl)ethanol, 2-(3-thienyl)ethanol, 2-thiopheneacetic acid, 3-thiopheneacetic acid, 2-thiopheneacetonitrile, 2-thiophenecarbonitrile, 2-thiophenecarboxamide, 2-thiophenecarboxylic acid, 3-thiophenecarboxylic acid, 2-thiophenecarboxylic acid hydrazide, 2,5-thiophenedicarboxylic acid, 2-thiopheneethylamine, 2-thiopheneglyoxylic acid, 2-thiophenemalonic acid, 2-thiophenemethanol, or 3-thiophenemethanol, wherein, when said electrically conductive polymer comprises polypyrrole, said protective agent is selected from pyrrole-2-carboxylic acid or 1-(2-cyanoethyl)pyrrole, and wherein, when said electrically conductive polymer comprises polyphenylenevinylene, said protective agent is selected from benzoic acid, benzenethiol, benzenesulfonic acid, 3-vinylbenzoic acid, or 4-vinylbenzoic acid. an electrically conductive polymer, and at least one metal nanoparticle coated with a protective agent, wherein said protective agent comprises a compound comprising a first part that has at least part of a molecular backbone of said electrically conductive polymer and a second part that interacts with said at least one metal nanoparticle, wherein said electrically conductive polymer is selected from polyaniline, polythiophene, polypyrrole, polyphenylenevinylene, polythienylenevinylene, and derivatives thereof, wherein, when said electrically conductive polymer comprises polyaniline, said protective agent is selected from 4-aminothiophenol, 2-aminothiophenol, 3-aminothiophenol, 2-aminobenzenesulfonic acid, 2-aminobenzoic acid, 3-aminobenzoic acid, 4-aminobenzoic acid, 2-aminobenzonitrile, 3-aminobenzonitrile, 4-aminobenzonitrile, 2-aminobenzyl cyanide, 3-aminobenzyl cyanide, 4-aminobenzyl cyanide, N-phenyl-1,2-phenylenediamine, N-phenyl-1,4-phenylenediamine, or a copolymer of N-vinylpyrrolidone and N-phenyl-N'-(3-methacryloyloxy-2-hydroxypropyl)-p-phenylenediamine, wherein, when said electrically conductive polymer comprises polythiophene or polythienylenevinylene, said protective agent is selected from 3-(2-thienyl)-DL-alanine, 4-(2-thienyl)butyric acid, 2-(2-thienyl)ethanol, 2-(3-thienyl)ethanol, 2-thiopheneacetic acid, 3-thiopheneacetic acid, 2-thiopheneacetonitrile, 2-thiophenecarbonitrile, 2-thiophenecarboxamide, 2-thiophenecarboxylic acid, 3-thiophenecarboxylic acid, 2-thiophenecarboxylic acid hydrazide, 2,5-thiophenedicarboxylic acid, 2-thiopheneethylamine, 2-thiopheneglyoxylic acid, 2-thiophenemalonic acid, 2-thiophenemethanol, or 3-thiophenemethanol, wherein, when said electrically conductive polymer comprises polypyrrole, said protective agent is selected from pyrrole-2-carboxylic acid or 1-(2-cyanoethyl)pyrrole, and wherein, when said electrically conductive polymer comprises polyphenylenevinylene, said protective agent is selected from benzoic acid, benzenethiol, benzenesulfonic acid, 3-vinylbenzoic acid, or 4-vinylbenzoic acid.