TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The temperature is below 200degreesC, most preferably room temperature. At least a portion of the metal oxide nanoparticles are interconnected via mechanical or electrical bridge formed by reactive group(s) binding with the metal oxide nanoparticles. The metal oxide nanoparticles are formed as a thin film on a substrate. The substrate is dipped into the solution comprising the polymeric linking agent. The solution comprising the polymeric linking agent is sprayed onto the substrate or dispersed on a substrate.Preferred Components: The metal oxide nanoparticles comprise a chemical structure, MxOy. They comprise titanium oxides, zirconium oxides, zinc oxides, tungsten oxides, niobium oxides, lanthanum oxides, tin oxides, terbium oxides, and/or tantalum oxides.x and y = integers;M = Ti, Zr, Sn, W, Nb, Ta, or Tb.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Method: The temperature is below 200degreesC, most preferably room temperature. At least a portion of the metal oxide nanoparticles are interconnected via mechanical or electrical bridge formed by reactive group(s) binding with the metal oxide nanoparticles. The metal oxide nanoparticles are formed as a thin film on a substrate. The substrate is dipped into the solution comprising the polymeric linking agent. The solution comprising the polymeric linking agent is sprayed onto the substrate or dispersed on a substrate.Preferred Components: The metal oxide nanoparticles comprise a chemical structure, MxOy. They comprise titanium oxides, zirconium oxides, zinc oxides, tungsten oxides, niobium oxides, lanthanum oxides, tin oxides, terbium oxides, and/or tantalum oxides.x and y = integers;M = Ti, Zr, Sn, W, Nb, Ta, or Tb.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polymeric linking agent comprises a long chain macromolecule, which comprises a backbone structure similar to a chemical structure of the metal oxide nanoparticles, and reactive group(s) chemically bonded to the backbone structure. It comprises poly(n-butyl titanate). The solvent of the solution comprises n-butanol.