Growth of Black TiO2 Quantum Dots by Solution‐Based Electrochemical Process

Black titanium dioxide (TiO 2 ) quantum dots (QDs) are grown by a solution‐based electrochemical process and an effect of KCl concentration on the growth is investigated. The electrochemical process is demonstrated as a simple one‐step process for the growth of black TiO 2 QDs in the solutions via bottom–up process. From the absorption spectra, the absorption appears for an entire visible wavelength (400–700 nm) implying a black TiO 2 property. The average size of the black TiO 2 QDs is about 4.5 nm from the transmission electron microscopy results and is similar to all KCl concentrations. This indicates that KCl concentration has no effect on the particle size, but has effect on the hydrodynamic size of TiO 2 QDs. The black TiO 2 QDs can be produced by the hydrogenation process of hydrogen ions during electrochemical process. The obtained black TiO 2 QDs can be further explored as an electron‐transporting layer for a perovskite solar cell application.