“…Rutile is the most stable form of TiO 2 , whereas anatase and brookite are metastable and transform to the rutile phase upon heating [6,[12][13][14]. Conventional methods to prepare TiO 2 thin films are pulsed laser deposition (PLD) [15,16], RF magnetron sputtering [17][18][19] plasma enhanced chemical vapor deposition [20], and sol-gel methods [6,15,21,22], among others. Focusing on the solgel method, it is one of the most attractive techniques for thin-film deposition, because of low cost, non-vacuum requirements, large area deposition, and low temperature processing.…”