Solution processable formation of a few nanometer thick-disordered overlayer on the surface of open-ended TiO2 nanotubes

Herein, we designed vertically aligned TiO2 nanotube arrays, in which a very thin disordered overlayer approximately a few nm thick was formed via a room-temperature solution process. At the optimal overlayer thickness, the TiO2 nanotube arrays yielded a photocurrent density of up to ∼1.75 mA cm-2 at 1.23 V vs. RHE, approximately twice that of the pristine one.