Stabilization of titanium oxide films for highly transparent coatings

Abstract

A sol-gel material for overcoating a surface-relief structure includes a titanium(IV) precursor, and a titanium oxide stabilizer including ROC(O)OR, RC(O)OR, or a combination. Rand Rinclude alkyl or alkene groups optionally containing carboxylate, alcohol, or ester functionalities, such as propylene carbonate (PC). Rand Rinclude alkyl or alkene groups optionally containing carboxylate, alcohol, or ester functionalities, for example, a lactone such as gamma butyrolactone (GBL). In some embodiments, the sol-gel material includes a source of sulfate or phosphate anions, an acid, a base, a peroxide, a surfactant, a cross-linker, a flexibilizer, a toughener additive, a solvent, or a combination thereof. In some embodiments, the sol-gel material is annealed at a temperature between 50-150° C., and then annealed at a temperature between 200-300° C. In some embodiments, the sol-gel material is cured using ultraviolet light before annealing at a temperature between 200-300° C.