TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: Second coating layer comprises (in pts.wt.): N-type semiconductor (30-50), waterborne light-cured resin (25-45), electric conductive material (4-8), photoinitiator (1-2), stabilizer (0.2), flatting agent (0.2), antifoaming agent (0.2) and wetting dispersant (0.2). Third coating layer comprises (in pts.wt.): P-type semiconductor (30-50), waterborne light-cured resin (25-45), electric conductive material (4-8), photoinitiator (1-2), stabilizer (0.2), flatting agent (0.2), antifoaming agent (0.2) and wetting dispersant (0.3-0.6). The first layer comprises (in pts.wt.): waterborne light-cured resin (40-50), reflective material (5-15), photoinitiator (2-5), stabilizer (0.2), leveling agent (0.4), defoamer (0.3) and wetting and dispersing agent (0.1-0.2). The fourth coating layer comprises (in pts.wt.): waterborne light-cured resin (40-50), modified 1200 meshes talcum powder (4-6), hydrophobic auxiliary agent (0.4), anatase titanium dioxide (0.2), photoinitiator (2-5), stabilizer (0.2), leveling agent (0.4), defoamers (0.3) and wetting and dispersing (0.1). Preferred Components: N-type semiconductor is doped silicon crystal of phosphorus or antimony or sulfur incorporated in gallium arsenide. P-type semiconductor is doped silicon crystal of boron or cadmium or zinc incorporated in gallium arsenide. Waterborne light-cured resin is selected from copolymer type acrylate resin, epoxy acrylate resin or urethane acrylate resin. Electric conduction material is selected from electric conduction mica powder, titanium pigment or electric conduction graphite. Photoinitiator is selected from 1-chloro-4-hydroxy-thioxanthone or 2-hydroxy-thioxanthone. Stabilizing agent is selected from hydroquinone, pmethoxy phenol, benzene or ketone. Flatting agent is selected from polyacrylate or organic silicon resin. de-foaming agent is selected from n-butyl alcohol, tributyl phosphate or organic silicon resin. Wetting dispersant is selected from polyoxyethylene, polymethyl acrylate or acrylate acrylic acid copolymer. Reflective material is glass beads. Metal in leading-out electrode is aluminum, calcium, silver or magnesium.